Variations between norse/ nordic/ scandinavian and germanic/ german/ teutonic myths
Around any common cultural system could be after generations and generations of spread more than a large distance, evolving influences from neighbors, and progressively diverging languages. For which it’s worth, you can create root words for proto-Germanic types of most of the common gods of Germanic mythology — *Thun-raz for Thorr/Thor/Donar, etc. I’m not sure …