Hitler also displayed a sort of fatalism common of many who...

Hitler also displayed a sort of fatalism common of many who survived the trenches of the First World War - in Hitler's case bordering on self-destructive nihilism, and I think it's possible to infer something about his spiritual beliefs from this.

It's hard to understate the influence his war experiences had on his later perception IMO. The sheer waste of life and constant imminence of death brought home to him and most other veterans the tenuous link we have with life.

Hitler became obsessed with his legacy and the legacy of "his" people, and this suggests he saw his legacy as the only afterlife he was likely to have.

This and his other actions do not suggest a man who believed in God or the afterlife. Several of the other top Nazis were neo-Pagans interested in pre-Christian Germanic gods (who were similar to the Norse gods) but Hitler doesn't seem to have shared their interest for anything more than another tool to manipulate people to his will by diminishing the influence of the Church and the un-Nazi Christian values of the German people (after all, Thou Shalt Not Kill is a pretty hard one to reconcile with Nazism).