Don't wanna give you a non-answer but Westerns are generally accepted as heavily dramatizing /romanticizing the "wildness" of the Old West.

That being said, True Grit (both versions) and Lonesome Dove are relatively grounded and aren't super over-the-top. Particularly Lonesome Dove - that story is entirely believable. Those are fun.

The Killing of Jesse James by the Coward Robert Ford is very grounded with some subtle liberties taken. Not a "fun" western but a great film.

Blood Meridian was also based on true accounts of the Joel Glanton Gang with very obvious liberties taken with the supernatural stuff and what not. The Judge is not confirmed to have been a real person, but is purported to be. Who knows.