Christianity and it's attendant liturgical documents and period artifacts and accumulated oral history are the proof.
The fact that Christians exist, and the fact that they have written about their beliefs, are proof that their beliefs are true and based on facts? You don't see a problem with that argument?
Counterpoint: Hindus exist, and have written about their beliefs (for longer than Christians have). Ipso facto, Hinduism is the one true, correct religion and is based on facts.
I’m not addressing Christians at all
¯\_(ツ)_/¯
You're not concerned with evidence if you're reflexively denying it.
Wait, do you really think that atheists deny that Christians exist? Do you actually think that's what we're talking about? That's a whole new one. Otherwise you're committing a major strawman fallacy. I don't even know how to respond to that. It's utterly batshit.