Muslims pride themselves in believing that they worship 1 god called Allah, if this is true then is it possible that Allah converted to Islam? How can a god convert to Islam, if Allah converted to Islam this means there’s another Allah greater than him.
Let me direct you to their most trusted source the Qur’ān, since Muslims reject the Bible we don’t need to use the Bible to prove Islam is false because their own beliefs are full of contradictions. In Ali ‘Imran Allah took his Shahada, it reads:

[3:18] Allah bears witness that La ilaha illa Huwa (none has the right to be worshipped but He), …
How is Allah reverting to Islam unless there’s another Allah, perhaps our Muslim friends will be willing to explain how a god is becoming a Muslim?
This is why Allah doesn’t know if Allah will forgive, certainly if Allah is god he would know if he’s going to forgive someone or not, but Allah is saying he’s not sure (“it may be”).

[4:99] … it may be that Allah will pardon them. …
If Allah is god then he should say without question if he will pardon them or not, but here in Surah 4:99 Allah is unsure and says “it may be” he’s not sure that he will pardon them? And who is Allah if this is Allah speaking in Qur’ān, is he talking about another Allah just as he said there are other creators [Surah 23:12-14].

[9:43] May Allah forgive you …
Again Allah doesn’t know if Allah (another god) will forgive, this is the only way to make sense of the Qur’ān. If the Qur’ān is Allah’s literal word then he’s (Allah) is the one doing the talking in Qur’ān. Then Allah would be speaking to himself, why can’t Allah speak plainly and say “I will forgive you”?
Conclusion
The Qur’ān is a book from a god who doesn’t know if you can be forgiven because another Allah is the one who “May forgive”? This is confusing and cannot be a book from God. How is it their god took Shahada and converted to Islam as found in 3:18? These are the question we are asking Muslims to explain as their religion makes no sense.
We appeal to Muslims to search out these truths for themselves, if they’re not afraid of the truth then these theological problems should be addressed. Christians have since the beginning been upfront in our beliefs, they have been tried and tested and remain firm because they are founded upon the solid and sure Rock which is Jesus Christ Himself.
The LORD [is] my rock, and my fortress, and my deliverer; my God, my strength, in whom I will trust; my buckler, and the horn of my salvation, [and] my high tower.
Psalm 18:2