The practical problem is that calling God's existence logical tends to make doubt look like a failure, so honest disagreement gets dismissed instead of discussed. I just don't see how something that big can be pinned down by logic alone, honestly. Maybe I'm missing it.

But doesn't logic only work on things we can actually check? My opponent makes a fair point about everything needing a cause, and I'm not sure how to answer that. Still, God feels too big to squeeze into that kind of reasoning.

I get wanting a reason for everything, and my opponent is right that causes matter. But logic only gets you as far as your starting assumptions, and nobody can check the ones about the universe before it existed. That's why I still feel this is belief, not proof.