Book suggestions for accepting Allah?

Assalamu alaikum, I’m finding it tough to embrace the idea of Allah. The concept of Him being the first existence seems just as puzzling to me as an endless chain of causes. I also can’t wrap my head around why Allah is a sensible reason for our being here. If I were to believe in God, I’d choose Islam. I was raised Christian, but the Bible has been changed and all that. Islam’s scripture is the only one that stands up to scrutiny. I’m looking for a book to help me feel more certain about these matters. I sense there’s hope. I follow a Muslim debater who knows so much about ideas he doesn’t even agree with, yet he remains Muslim. So, I figure with enough learning, I could reach his conclusion. Jazakallah khair for reading, hope I made sense. P.S. Videos also welcome, forgot to mention that earlier.