I would agree that Cher and Sinatra are examples of the best. Also agreed that Kristofferson has blundered into too many movies so bad that there was nothing anyone could do with them; anyone else actually spend money to see the "A Star is Born" remake? Urrrrrp!
Streisand also has laid some other true stinkers.
Getting down to absolute rock bottom, it would be hard to choose between Bob Dylan as Alias in "Pat Garrett and Billy the Kid", and Glen Campbell's performance in "True Grit".
At the risk of drift, I thought "Pat Garrett and Billy the Kid" was a hopelessly garbled mess, in the midst of which the Slim Pickens death scene came off as sublime.