That's an interesting question. There is a book by Michael Hesemann, a German historian, in which he is interpreting Hitlers religion (that is actually the title of the book) like this:
Hitlers plans where going towards a "German pseudo-religion". Hitler got his first ideas from the "Ostara"-magazine, that was published between 1903 to 1931 and propagated Aryan and antisemitic theories.
The publisher, an Austrian named Jörg Lanz von Liebenfels, wanted to get his followers to convert to Protestantism, but most of the Austrian population was strictly catholic at this time, so he failed.
So Hitler, not wanting to share the fate of Liebenfels, had to keep an catholic facade. He needed the church (catholic and protestant) to get a chance to achieve his goals. Hitler found his idol in Richard Wagner. In his beliefs, Jesus Christ was Aryan, but was affected and influenced by the Jews and therefore his teachings were distorted.
Hitlers target was actually to destroy Christianity to make way for his German religion, but considering the percentage of German Christians, this was not possible, so Hitler started with the Jewish population.
Nonetheless there have been assaults on catholic churches and priests too.
According to Hesemann, the destruction of Christianity in the Third Reich would have been Hitlers plan after the "Endsieg".
So, personally, I can't say if that is the truth, but it seems reasonable in some factors, but I want to close with a quote from Hitler, spoken in 1941:
Christianity is a rebellion against natural law, a protest against
nature. Taken to its logical extreme, Christianity would mean the
systematic cultivation of the human failure.
Michael Hesemann - Hitlers Religion