Sounds like “A Man Called Horse” from the ‘70’s starring Richard Harris. Cameron could have saved 300 million and shot the remake with a few horses, teepees, vintage military costumes and a drunken irishman.
I remember that dopey movie (and its sequels) during the 1970s-1980s.
I think one of the “Man Called Horse” movies was playing as the B flick at a drive-in when I was with a girlfriend.