A Catholic responded to my claim that the catholic canon wasn’t settled until the Council of Trent. Here was his response:

This is false. It was not until the Synod of Rome under Pope Damasus in A.D. 382, followed by the Councils of Hippo and Carthage, that the Catholic Church defined, albeit non-infallibly, which books made it into the New Testament and which didn’t. Probably the council fathers studied the (complete) Muratorian Fragment and other documents, including, of course, the books in question themselves, but it was not until these Councils that the Church officially settled the issue. The plain fact of the matter is that the canon of the Bible was not settled in the first years of the Church. It was settled only after repeated (and perhaps heated) discussions, and the final listing was determined by the pope and Catholic bishops.

Pope St. Damasus is an interesting person in the Catholic Church. His rise to the Papacy and later “Sainthood” makes an interesting case:

By the way, shortly thereafter (365/6), Liberius and Felix both died at the around same time. While Damasus was the “successor” of Felix, the “successor” of Liberius, Ursinus, found himself and 137 of his followers brutally murdered by a mob of pick-axe-bearing gravediggers hired by Damasus. Damasus “reached the see of Rome by walking over the corpses” of the followers of Ursinus, (Hanson cites bot Sozomenus and Theodoret in this). Damasus, by the way, is “Pope St. Damasus”, for his work in re-writing the history of Rome to include the ancient church.

https://triablogue.blogspot.com/2015/01/how-pope-liberius-adopted-arianism.html

The problem with appealing to the early councils is that they aren’t authoritative in your Church. If Rome didn’t arbitrarily define canon the way they did at Trent, then you probably wouldn’t be defending the canon you hold to now. Even after the Councils of Hippo, Carthage, and Rome people debated the canon. It was still being debated until the Reformation. Cardinal Cajetan, for example,  didn’t contain some of the books that Rome has defined as canon in his commentary on the books he thought were authentic. The same is true of Cardinal Francisco Jiménez de Cisneros (Cardinal Ximenes, 1436-1517) who was commissioned by the Pope to provide his polyglot (in which he denied the apocryphal writings). William Webster wrote:

“Cajetan wrote a commentary on all the canonical books of the Old Testament which he dedicated to the pope. He stated that the books of the Apocrypha were not canonical in the strict sense, explaining that there were two concepts of the term ‘canonical’ as it applied to the Old Testament. He gave the following counsel on how to properly interpret the decrees of the Councils of Hippo and Carthage under Augustine:

Here we close our commentaries on the historical books of the Old Testament. For the rest (that is, Judith, Tobit, and the books of Maccabees) are counted by St Jerome out of the canonical books, and are placed amongst the Apocrypha, along with Wisdom and Ecclesiasticus, as is plain from the Prologus Galeatus. Nor be thou disturbed, like a raw scholar, if thou shouldest find anywhere, either in the sacred councils or the sacred doctors, these books reckoned as canonical. For the words as well of councils as of doctors are to be reduced to the correction of Jerome. Now, according to his judgment, in the epistle to the bishops Chromatius and Heliodorus, these books (and any other like books in the canon of the bible) are not canonical, that is, not in the nature of a rule for confirming matters of faith. Yet, they may be called canonical, that is, in the nature of a rule for the edification of the faithful, as being received and authorised in the canon of the bible for that purpose. By the help of this distinction thou mayest see thy way clearly through that which Augustine says, and what is written in the provincial council of Carthage.129

129 Cardinal Caietan (Jacob Thomas de Vio), Commentary on All the Authentic Historical Books of the Old Testament, In ult. Cap., Esther. Taken from A Disputation on Holy Scripture by William Whitaker (Cambridge: University, 1849), p. 48. See also B.F. Westcott’s A General Survey of the History of the Canon of the New Testament (Cambridge: MacMillan, 1889), p. 475.”

This is hardly the end of issues for the Catholic’s apologist appeal. For even members of the same councils still left with different canons. For example, Jerome, Epiphanius of Salamis, and Augustine both attended and held different canonical lists.

Jerome, who had copied Hilary’s canonical list for Rufinus and who began his study of Hebrew during his first visit to Antioch a number of years before, later sharpened his acceptance of the Hebrew OT canon as the normative list of canonical books. Because of his knowledge of Hebrew he not only rejected books he called apocrypha (Wisdom, Sirach, Judith, Tobit, the Shepherd of Hermas), but he also rejected Maccabees and the additions to Daniel and Esther. 236 He did not accept Baruch as a part of Jeremiah. Except for a quickly produced translation of Tobit and Judith made at the request of his friends and the inclusion of the additions to Esther in his Latin Bible, Jerome did not translate these books. Jerome left two canonical lists. One appears in a letter to Paulinus. 237 The more important list is in his preface to his translation of Samuel and Kings. This preface he entitled the Helmeted Preface, intending it to be a defense of the criticism he knew he would face, especially from the western Christian churches. In this preface he lists the books according to the rabbinic system of Law (5 books), Prophets (8), and Writings (9). The number of books is twenty-two, corresponding, as Jerome notes, to the number of letters in the Hebrew alphabet. He also notes that some Jews reckon the books as twenty-four and comments that this is achieved by separating Ruth from Judges and Lamentations from Jeremiah. He compares the reckoning of twenty-four books to the number of elders in the book of Revelation. He even notes that the canon could be reckoned as twenty-seven books (the number of Hebrew letters if one also counts the five letters that have special final forms) by splitting the double books (Samuel, Kings, Chronicles, Ezra-Nehemiah, Jeremiah-Lamentations). Jerome’s attitude toward the canon is the polar opposite of Augustine’s. He recognizes only the books contained in the Hebrew canon and only in their Hebrew form. He does not recognize the right of the church to define the canon based on its traditions, but defends the canon received from the synagogue as the true canon.

Steinmann, Andrew E. The Oracles of God (Kindle Locations 2734-2750). Concordia Publishing House. Kindle Edition.

Furthermore, Roman Catholics disagree with the Council of Rome’s claims about authorship:

As with the other two councils, the Council of Rome specifically mentioned the Deuterocanonical books of Tobit, Judith, and the two books of Maccabees by name.  Unlike the two later councils, it also specifically mentions Wisdom and Sirach.  Pope Damascus I who reigned over this first council lists Solomon’s books as only being three (Proverbs, Ecclesiastes, and Song of Solomon), while listing Wisdom and Sirach as separate non-Solomonic books.  The latter two councils’ conflict with Rome and Damasus by including Wisdom and Sirach as being part of the five books of Solomon.  Despite all three councils accepting these same books, they were not “universal” in their agreement of which ones were attributed to Solomon.

Christie, Steve. WHY PROTESTANT BIBLES ARE SMALLER: A Defense of the Protestant Old Testament Canon. Christian Publishing House. Kindle Edition.

A Catholic cannot appeal to their authority merely for canonical purposes and ignore it for its other decrees. It seems that Catholics wish to merely pick and choose what parts of regional council statements are authoritative. There are also possibly further historical problems here as to whether Baruch and the epistle of Jeremiah were omitted or were considered a part of Jeremiah. The problem is that it isn’t clear this is how historical contemporaries treated Baruch and the epistle of Jeremiah. Cyril of Jerusalem doesn’t include them in Jeremiah, but rather he lists them as separate books. Steve Christie wrote about this:

As previously mentioned, the Deuterocanonical book of Baruch and the epistle of Jeremiah were also not in the list at the Council of Rome, despite listing the other six Deuterocanonical books explicitly.  The Council of Rome is more exhaustive than the two latter councils given it lists all the individual books of the canon by name, such as naming the twelve “minor prophets” separately.  The two latter councils simply refer to them as “the books of the twelve prophets.”  Yet, both Baruch and the epistle of Jeremiah are omitted – individually – from the lists of all three councils. In a letter addressed to Anthony Houston on EWTN.com, “It is to be noted that the book of Baruch was considered by some Church Fathers to be a part of the book of Jeremiah and as such was not listed separately by them.”154 This is arguably a reason why the Council of Rome did not list them individually, despite listing all of the other Deuterocanonical books and the individual “minor prophets” separately.  However, as mentioned in Chapter Two, Cyril of Jerusalem who lived during this time (A.D. 315 to 386) did list Baruch and the epistle of Jeremiah as separate writings from the book of Jeremiah, as well as Lamentations.  Origen of Alexandria listed “The Letter” of Jeremiah, as well as Lamentations, separately from the book of Jeremiah.155 Even the New Testament references the epistle of Jeremiah as a separate writing (1 John 5:21, cf. Epistle of Jeremiah v.72 NAB), distinct from the book of Baruch

Christie, Steve. WHY PROTESTANT BIBLES ARE SMALLER: A Defense of the Protestant Old Testament Canon . Christian Publishing House. Kindle Edition.

There is another issue between the two councils on the issue of the Septuagint’s I Esdras. Rome rejected it at the Council of Trent, but given the different classification at the Council of Rome, it was accepted in the canon of that time. This was argued by William Webster in a three-part article series 1, 2, and 3:

Again, Roman Catholic apologists argue that the canon was authoritatively settled for the universal Church at the Councils of Hippo and Carthage. However, the canon decreed by the North African Councils differed from that decreed by the Council of Trent in the sixteenth century on this one important point of the book of I Esdras. Hippo and Carthage stated that 1 Esdras and 2 Esdras were canonical, referring to the Septuagint version of 1 and 2 Esdras, the Bible their Latin version was based upon. In that version, 1 Esdras was the apocryphal additions to Ezra and Nehemiah not found in the Hebrew Bible, while 2 Esdras was the canonical Jewish version of Ezra/Nehemiah. The Jews only acknowledged Ezra and Nehemiah which they combined into one book. This was 2 Esdras in the Septuagint version. It was Jerome, who, out of a desire to adhere to the Hebrew canon, separated Ezra and Nehemiah into two books, calling them 1 Esdras and 2 Esdras respectively, thereby replacing the Septuagint I Esdras with the Hebrew Ezra and calling it I Esdras. This became standard for the Vulgate and the basis upon which Trent declared the Septuagint I Esdras to be noncanonical. 1 Esdras in the Septuagint then became 3 Esdras in the Vulgate and the other Apocryphal apocalyptic work of 3 Esdras became 4 Esdras in the Vulgate.

https://www.aomin.org/aoblog/roman-catholicism/bill-webster-responds-to-gary-michuta-part-ii/