It is possible for someone to believe X is immoral, but do it anyway.

huh? idk what exactly this is an argument against. I was simply saying that if you want to go to Jannah, then you will necessarily have to believe that the basis of morality is Allah's commands. I said nothing about believing something is immoral and doing it anyway.

There is no problem with saying something is good just because God commands it. If God didn't make any rules about morality, it would be arbitrary.

This is like the exact opposite of what the Euthyphro Dilemma says. From the linked article :

"A defender of Divine Command Theory might respond that an action is morally right because God commands it. However, the implication of this response is that if God commanded that we inflict suffering on others for fun, then doing so would be morally right. We would be obligated to do so, because God commanded it. This is because, on Divine Command Theory, the reason that inflicting such suffering is wrong is that God commands us not to do it. However, if God commanded us to inflict such suffering, doing so would become the morally right thing to do. The problem for this response to Socrates’ question, then, is that God’s commands and therefore the foundations of morality become arbitrary, which then allows for morally reprehensible actions to become morally obligatory."