The usual objection to the Christain transcendental argument is the notion that other worldviews are possibly true. There is an infinite set of worldviews according to them. That has force if we start with a view where possibilities are brute facts. The problem is that presupposes that Christianity is false. In Christianity, the facts of possibility are God’s facts. The Reformed view of Modality is thus:

The finite mind cannot thus, if we are to reason theistically, be made the standard of what is possible and what is impossible. It is the divine mind that is determinative of the possible. We conclude then that God’s knowledge of the universe is also analytical. God’s knowledge of the universe depends upon God’s knowledge of himself. God has made the universe in accordance with his eternal plan for that universe. Thus the very existence of the universe depends upon God’s knowledge of or plan for the universe.

The Defense of the Faith, 4th Edition; Van Til, Cornelius;Oliphint, K. Scott;Page 62