Two things: geography and popular support.

Most of Germany is a massive plain with super-dense settlement network. There is nowhere to hide for a partisan group and by 20th century it’s not possible for local chieftains to hold sovereign power as it’s easy to just move towns/regions. Nazis had no way to hide their potential guerilla operations, no way to rely on sympathetic locals in select places. Afghanistan is sparsely populated, with local communities, which sometimes can be isolated from each other due to terrain and distances. The entire country is mountains which have hardly ever been surveyed and are inhospitable to anyone not born there (and even then it’s just too easy to hide).

Yes, millions of Germans supported the Nazi party. But millions more were quietly against it or were “not interested in politics”. After WW2 the Nazi party was soundly beaten and the non-commited/antinazi Germans could build a civil society - in a land which had centuries of civic traditions. Whereas the Taliban have more commited supporters and weaponise the religion which already is very influential in any individual’s life in a land dominated by patriarchal clan social structures.