The downfall of Germany was for most part due to its attitude to its neighbors east. They did not treat these countries as just enemies, but intended to annihilate them as nations and transform the lands to amusement parks, fields, mines etc. with enslaved populations.
Germans treated western enemies completely differently. Even after occupation, they were never subjected to a program of nation-removal. Nor this was intended.
German attitude towards East and Russia, gave the gravest incentive for Russian people and elites to fight to the last breath, since there was no imaginable future for Russia inside a new order. This was a fatal mistake in part of Germany.
Unfortunately, similar attitudes still live on. We see parallel manifestations of the similar policy: Ukraine and Israel. In the case of Russia, since 1991 Western powers never tried/wanted a strong Russian nation as equal partner. Their schemes were similar to 1940s, albeit in more modern formats. Plundering and destroying whatever was left of Russia after Soviet collapse, with the final goal of doing what happened to Soviet to the Russian state, alerted Russian elites to the similar threat to their existence, thus Putin era.
Western powers are still in denial, they think/assume Russia could in a way or other annihilated and removed from the map. This is was a mistake in 1940s, it has been a mistake since 1991.
Israel treats neighbors with a similar attitude. It seems as if it cannot accept no country in the region worthy of independence or statehood. That seems to be the ultimate goal of all US wars in the region (US in many ways is acting like Israeli wehrmacht).
case in point: no amount of obedience or appeasement wrt Israel shown by Lebanon and/or new Syria would stop daily bombings from Israeli side. Israel does not need Arab friends or equals. It seems to need the lands (Lebenraum) and maybe some enslaved population. Nazi-esque attitude towards neighbors still prevails inside the Western policy attitudes (Israel is a Western power). The example of Ukraine/Russia showed the 21st century defeat of said policy. Is Israel next?