The commandment of faith

peace,
The arguments (as brought up, for example, by Rabbi Hasdai Karshakash and as you wrote in the trilogy) that negate the commandment of faith are: A. A mitzvah assumes that there is someone who commands, but this has not yet been proven, meaning that a person is not obligated to believe because first of all he has to come to the conclusion that there is someone who commands (of course, the wording can be refined, I wrote briefly) B. It is not possible to command in relation to facts, because we are forced into our own thinking.
Regarding the prohibition of engaging in the foundations of faith, you added two arguments in the trilogy: A. The mouth that forbade is the mouth that permitted in relation to reason, B. It is unreasonable to command the reduction of enlightenment and deepening in faith.
So far so good. But I have 2 questions:
A. You also cited Rabbi Hasdai Karshakash's two arguments against the commandment of faith as arguments to negate the prohibition on engaging in the foundations of faith. I did not understand why they are arguments against this:

1. With respect to the logical issue that a mitzvah presupposes someone who commands – after a person has come to the conclusion that he believes and accepts the laws of the Torah, what is the fallacy in saying that the Torah can command him not to investigate further? (Of course, assuming that he has not already completely renounced the Torah, and then the question returns, because the issue of there being no mitzvah without someone who commands returns).
2. Why is there a problem here of a commandment regarding facts? This is a completely normative commandment – for example, do not open books that you have heard are heretical.

on. I understand the benefit of the discussion of whether there is a prohibition on prohibition in the foundations of faith, but is there any benefit at all to the discussion of whether there is a mitzvah for believers?
Thank you very much!