“Allah is a singular entity that has no son. He is unknowable. Not the God of the Bible.”
You are accepting the Muslim view of God by saying so. Muslims acknowledge one true God. They just don’t know Him.
You are correct that the Muslim view of God is theologically incorrect.
What you are wrong about is that the one true God divided the languages, and has preserved for Himself a title in every language, and that title in Arabic is Allah.
Is the Muslim Allah the one true God. No. But what is the title of the one true God in Arabic? It is Allah. This is what Arabic Christians refer to as God.
The term “God” is English. Not everyone speaks English. The original Bible was in Greek and Hebrew. The term “God” does not appear in it anywhere. Not does the term “Jesus”. not in the original. These are translations into English.
Allah is the Arabic term for God. We do not have to convert Arabs to English speakers in order to correct their wrong theology about the one true God.