The strongest pieces of evidence comes from the Table Talk which is not really a reliable source considering that it is is a book of transcribed conversations that Hitler had with people in his circle. Some versions of this book that were translated from German to other languages contained fabricated statements not found in the original German manuscript. Sounds fishy to me. But that’s almost beside the point. Let’s say he was not a Christian for the sake of argument he still was able to use it to win over the German people who were predominately Christian and used it to justify the persecution of the Jews. It doesn’t really even matter what he felt on the inside.