I offer my opinion. Please be gentle.
Can we as human beings truly understand what Allah/God is in pure form?
Hopefully not in my opinion. 'God' is a word, an approach to an idea about something we can't see. For practical purposes it is, among other ideas, the idea that ultimate authority rests with no person, nor can any person define for others what is right and wrong. We can enforce laws and make laws, but we can't make things good or bad. We can't say that we have divine right to rule unless that is granted to us by a higher authority. This is an important idea in the legal processes where I live and in in many places. Its not embraced everywhere. Its a religiously based idea but also one which functions as the backbone of many legal systems. Here the government derives its authority from the people, but people are sworn in with "So help me God" which in law is not the name of someone but the idea that there is an authority above the people.
Can we say: this is Allah/God?
Is 'Allah' a name? 'God' isn't. It is an idea implying many things including that the divine cannot be expressed in words alone.
Does Allah teach anything which conflicts with the philosophically derived concept God? Some would say yes. For one thing Allah apparently teaches that believers are morally superior to nonbelievers, though I am not an expert on the Quran. I think have read some Quran passages indicating this, and it troubles me. This conflicts with God the concept in many NT texts. It may also conflict with the philosophically derived understanding of God, but I am not an expert on that. That would be something to inquire about with someone familiar with how that is derived.
Some people believe that certain races have superior moral character or that some bloodlines have. This has been the cause of much misfortune in this world among Christians, and I think it is incompatible with a successful church. With people who believe in God this is a malady which afflicts some but not others. Most today appreciate that most people are morally on somewhat equal footing and that no human is moral relative to God. I don't know what Allah teaches about it, but I have heard of passages in the Quran which suggest there are wicked bloodlines. This troubles me.
I have to admit that a morally superior person might be created, but I don't think its true, especially not in comparison to God who would dwarf us all as the Earth dwarfs apples and oranges. Such is the concept of God that a human would only be able to be so good without destroying ourselves. We would become like an insect that grew too large and became unable to move or like a lobster that was so large that it could no longer keep itself fed. Madness and self destruction would follow or death.
Is Allah invisible? God is never visible.
Does Allah have a shape? God has no shape.
Does Allah teach that all people have moral capability? The NT says that all people have access to wisdom from God, and this is called 'Conscience'. Does Allah teach that people can be guided by their conscience?
Does Allah have a physical form? The philosophically derived concept God involves no physical form for God. Neither does the NT assign God form but instead points out that God has no form. With Jewish scriptures this is not as clear, but I think they are probably similar in this respect.
There can be fighting and arguing about this topic. Some would have us to believe that God is our inaccurate understanding of Allah. To me that sounds like evidence that there is not agreement. I could just as easily claim the reverse, that Allah is an inaccurate caricature of God, but I don't. I don't say that, because its inflammatory and pushy; and haven't I already admitted that nobody fully understands God? Its better not to bring it up most of the time, but most people don't think of God and Allah in exactly the same way. The understanding that God is beyond comprehension goes a long way towards making it unnecessary to discuss it. Also helpful is the understanding that human minds are limited and only grasp facets of the whole truth.