I think the main issue with Crystal Skull was just that the Soviets aren’t as interesting as archeology/occult villains as the Nazis were in earlier films.

Soviets make good bad guys in spy or military drama films. If something is dealing with the occult or ancient archeology they just don’t carry the story as well as Nazi Germany who were actually serious about stuff like that.

It grounded Raiders of the Lost Ark in some key ways because it was somewhat believable that a bunch of Nazis were running around looking for something like that.

It’s the reason they are commonly used or referenced in stories about ancient occult objects. Even Uncharted 2 on PS3 had a whole scene dealing with NAZIs in Tibet looking for Shambala. Which made perfect sense in the story considering the history of Himmler and the SS and some of their programs they actually spent money on.