if Hitler had been allowed into architecture school like he wanted, the whole history of Europe would have been different

Is this a subtle difference from the real world, or just Harry thinking more deeply?

As I understand it (confirmed by Wikipedia), Hitler was rejected from a school for pictorial art, not architecture. However, Wikipedia has more: the art school recommended that he become an architect instead, and Hitler agreed. However, Hitler never bothered to apply to architecture school, because he lacked the necessary academic qualifications (including a high-school degree, which was rarer back then).

It's not clear from this if Hitler ever formulated the desire to attend architecture school, or if it was always simply impossible to him. The usual counterfactual hypothetical is "What if Hitler had gotten into art school?", but maybe "What if Hitler had tried harder in high school so that he could have qualified for architecture school?" is more realistic after all, given where his talents lay.

PS: I type this in the middle of catching up on MoR, while in the other room Order of the Phoenix is on the TV. But I've seen that before!