The second half of the question is less important than the first here.
This hypothetical presumes Adolf Hitler's death in April 1938, a month after German annexation of Austria. Death of natural causes, perhaps in a car crash. How does the NSDAP respond to the sudden leadership crisis? Are plans for Czechoslovak expansion put on hold? Does history remember Hitler in a much more positive light and elide over the destruction of Jewish rights and multiparty democracy?
Nothing in changes , Nazism was the main not just Hitler
My bigger question is whether Adolf Hitler is portrayed in a positive light in some "respectable" circles as a skilled statesman who annexed Austria and made Germany a great power again while the debacle of losing the war etc would just be blamed on his successor.