The prohibition of questioning regarding the tenets of faith

Hello Rabbi Michael, I wanted to ask you a question regarding the prohibition on interrogating other religions. This is what Maimonides wrote:
[2] Many books have been written by worshippers of idols about their worship, what is the essence of their worship and what are their laws and actions. The Holy One, blessed be He, commanded us not to read those books at all, nor to ponder over them, nor to contemplate any of their words. Even to look at the image of the form is forbidden, as it is said, "Do not turn to idols" (Leviticus 19:4). In this regard, it is said, "And lest you inquire of their gods, saying, 'How do they worship?'" (Deuteronomy 12:30) – that you do not inquire about the way of their worship, what it is, even though you are not a worshipper: for this makes you turn after it and do as they do, as it is said, "And I will do so also" (ibid.). [3] All these prohibitions are in one matter, and that is that one should not turn to idolatry; and whoever turns to it in the way in which he does an act, then he is defective.
And it is not only idolatry that is forbidden to be pursued in thought, but any thought that causes a person to uproot the main principles of the Torah – we are warned not to bring it to our hearts, and we will not be distracted by it and think and be drawn to the musings of the heart: because the mind of man is short, and not all opinions can attain the truth on its own; and if every man pursues the thoughts of his heart, he will be found destroying the world according to his short-sightedness.
How: Sometimes he will abandon idolatry; and sometimes he will think exclusively about the Creator, whether He is or not, what is above or below, what is before or behind; and sometimes about prophecy, whether it is true or not; and sometimes about the Torah, whether it is from heaven or not. And he does not know the qualities to judge by until he knows the truth about his idols, and he finds himself coming to the aid of the gods.
And the Torah warned about this matter, and it says in it, "And do not turn after your hearts and after your eyes, after which you prostitute yourselves" (Numbers 15:33) — meaning, each of you should not be drawn to his own short-sightedness, and imagine that his thinking reaches the truth. Thus the Sages said, "After your hearts," this is adultery; "and after your eyes," this is prostitution. And this, although it causes a person to be expelled from the world to come, does not have any punishments.

All of these prohibitions seem very puzzling. Let's assume a hypothetical situation in which there are two people who each belong to a different religion: religion A and religion B (and let's assume for the sake of this matter that one is true and the other is false). In each religion (A and B) there are prohibitions such as those that prohibit inquiry about the other religion, lest a person become confused and abandon his religion. Both people try to be as righteous as possible, and therefore both refrain from inquiry about the other's religion. It turns out that one of them is certainly wrong, while in a situation where there was no such prohibition, it is possible that through open discourse, both would have reached the truth.
Beyond that, if we define as books of error books books that distance a person from the true religion. Religious scholar A could claim to himself that the books he has read to date may be books of error books (this is what religious scholar B claims). Religious scholar A asks himself, then, should I first find the true religion so that I can definitely avoid the prohibition of reading books of error books (since we defined books of error books as books of false religion). It turns out that he completely uproots these prohibitions of error books, because as long as a person has doubts about the truth, the prohibition has no meaning, and once a person no longer has doubts after investigating it, there is no point in the prohibition. Therefore, I do not understand how it is possible that the Rambam ruled on these prohibitions?