I don't think it's necessary to believe in eternal damnation in order to be a Christian. Hans Urs von Balthasar and David Bentley Hart are two preeminent theologians who would agree. That's just from the little I know on this subject.
I mean it’s surely possible to find theologians that don’t but it’s the official doctrine of all real existing sects, and regardless, even if you forget about eternal damnation then is still implies that you aren’t saved unless you put faith in Christ.
My other issue with Christianity is that Jesus comes off as genuinely unhinged sometimes. For example, when he tells the Jews that the only way to be saved is to eat his flesh, and when they say “surely that’s just a metaphor, how do we eat your flesh?” he says “no, I’m being totally serious”. There are a bunch of times in John where the stuff he is saying sounds crazy even to his disciples. Let me ask you, if someone today came and said those things, would you believe them? The only difference between him and a modern person on drugs is the records of his supposed miracles
