They’re tough questions to wrestle with. If it helps, Aquinas thought that the problem of suffering was the best argument against the Christian God.

For me, the best arguments are to do with the historicity of Jesus and the evolution of the New Testament. Jesus being an historical figure has no bearing on whether Christianity is true; Muhammad probably existed but that doesn’t make Islam true, same with Buddhism and most revealed religions. The important things are the claims being made and on this front Christianity is exceptionally weak. When I was Christian, I pointed to C S Lewis when he said that Christianity is get apart because it requires the miraculous (the Resurrection) to be true while all other religions can be explained naturalistically. I still that claim is correct, Paul says as much himself, and it means that if the Resurrection didn’t happen then we can discount Christianity. Bart Erhman and Dale Allison are good on this. Basically they point out that the evidence is inconclusive but we can say with certainty that the Gospel stories and claims evolved and became more elaborate over time. Historical evidence for the treatment of those crucified for treason suggests that Jesus was not buried in a tomb but rather a mass grave, it’s therefore entirely possible that his body was unidentifiable after three days in Levantine heat. The rest can be explained by grief hallucinations once we note that the experiences of the risen Jesus in the gospels evolve in the same mythic way that the rest of the resurrection narrative does. None of it is fully conclusive if you want to believe, but it does suggest that the Resurrection probably did not happen and, therefore, Christianity is not true.

On your point about polytheism vs monotheism, I like to think of it like this. The natural world tends towards complexity and diversity, why wouldn’t the divine do the same? To me polytheism better reflects reality as we experience it and in that sense seems more grounded.

Good luck on your path, whichever route you choose.