Performing a commandment at God's command is against practical rationality?

Hello.
In the first lesson on faith and its meaning, you said that the question of why one should keep the commandments after believing in God and in the status of Mount Sinai is irrelevant, because God is the one who obligates, and therefore it is right to do His commandments.
I agree with you that performing a mitzvah in this sense is correct, but I don't think it solves the problem.
Even if I believed 100% in God, and that He gave commandments, but you told me that doing them would harm (utilitarian) the environment and me in the next world and in this world, I would not do the commandments, even though it is true. Because doing it will only lead to bad results, and it is not wise, and not nice (on the part of others), and what do I care if it is true, if it causes evil?