In WWII most of the German people were (and most likely still are) catholic. I don’t know if anyone really knows how religious Hitler was
Well, no. In WWII, about a third of Germans were Catholic (mostly in the south). About a third were Protestant (mostly in the north). And the rest weren’t Christian at all. The numbers are close to the same today with the same geographical spread in what used to be West Germany. East Germany had the religion basically stomped out of it during Communist rule, and so doesn’t any religion as a majority.
Of course, Hitler wasn’t from Germany. He was Austrian. But Austria is mostly Catholic, and early in his life Hitler’s family moved to and from southern Germany. . .where Catholicism was the main religion. His parents were Catholic, and he went to a Benedictine school. So he certainly was exposed to Catholicism more than any other religion when growing up.
In his public speeches, Hitler sometimes spoke positively of Catholicism, as well as Christianity and Protestantism. But those were public speeches, which were basically propaganda. He would say whatever was needed to sway the audience, be it true or not. Since about two-thirds of Germans were Christian, praising Christianity is a good move to gain their support. Also, Hitler and the Nazis were usually pointing out (rightly enough) the Communists as one of the biggest—if not the biggest—threat to Germany. . .and Communism is generally associated with atheism. So Hitler had to try to portray himself as a good ol’ godly folk to not just appeal to the Christian majority, but also to contrast himself against the Communists.
In private, though, he apparently often spoke out against Catholicism or Christianity or organised religion overall. The diaries of intimates of his such as Goebbels and Speer include summaries of talks with Hitler in which he was expressing religious views far removed from those in his public speeches. And people who knew him when he was younger said that while he was originally enamoured with Catholicism, he became disillusioned with it at a fairly young age. . .though he was more than happy to copy its use of imagery and pomp in later years to glorify Nazism. His marriage ceremony was entirely non-religious in nature, even though there were plenty of priests and ministers whom he could have called upon.
So all in all, adult Hitler was probably only religious when it suited him to appear so.