There’s Boba’s voice. But developing a different accent is possible.
I always just assumed Fett’s voice was mechanically altered by the mask, just like Vader’s and Leia’s/Boussche’s–even before “knowing” that he was “always supposed to be” a clone of some stilted kiwi.
I mean, is James Earl Jones’s voice “inconsistent” with Hayden’s? (Please don’t give LucasFilm any more ideas!!!)