How would you say for dinner in Japanese would you say Bangohan no tame ni? Or is that only for verbs for a person
ために means "for the sake of...", so it can't be used in this context. Here, you could use a simple construction with は.
For example: ばんごはんは、ラーメンを食べました。(I ate Ramen for dinner.)
Just に can also be used. Like "as/for something" ばんごはんにカレーを食べた。(I ate curry for dinner)