GTK plasma theme not being applied on wayland

Are you sure you changed the theme here?

Either way, you could manually edit the file and replace Sweet-Dark with the EXACT name of your GTK Theme.
I don’t think you need to relogin but plz do so just in case.

Other thing you can try is open up your favorite Terminal window and hit this:

GTK_THEME=emacs input-remapper

Did it change the theme?