What Is the Best Argument for the Existence of Allah?

In the comments I've been asked by Christian apologists Trent Horn and C. Michael Patton to tell my readers what I consider the best argument to the existence of God. Okay. Here goes. The best argument on behalf of Allah is the moral argument to his existence.

Let me quote from my book Unapologetic:
Regarding the case for the existence of God due to objective morality, the moral argument to the existence of God depends on one’s morality. Many Christian theologians and philosophers attempt to make an argument from the existence of objective morality to the existence of their God, who just happens to have the same kind of morality they do, surprise!
Take for example the Islamic State (or ISIS). They could make the same moral argument to the existence of their god, using their own morality, where it’s okay to rape women, own slaves, chop off heads, and burn people alive. Christians would have to agree with their moral argument, but subsequently disagree with their morals. However, the morals of ISIS are used as evidence that their god exists, just as the specific morals of Christians (depending on the century) are used as evidence their god exists. So certain kinds of morals lead to certain kinds of gods. Or certain kinds of gods are used to justify certain kinds of morals. Which comes first? I’m as sure as sure can be that the morals come first.
The moral argument works in an inductive manner with some degree of probability to it above 50%. But it only works if one's morals are absolute, unchanging and also good. Since it's demonstrably and unmistakably the case that morals are not absolute and unchanging then there cannot be an absolute and unchanging divine lawgiver. So even the best argument to the existence of Allah isn't a good argument at all. This applies to the Christian god Yahweh as well. Even the best argument to the existence of Yahweh isn't a good argument at all.

Discuss. What do you think of my answer?