Having a quality Backup QB is essential but not necessarily the norm. Miami seems to have had an above average Backup QB since Earl Morrell was here.
With that being said, I'd hope, Fitzpatrick, doesn't leave for what he feels is greener pastures, elsewhere. IMHO he's in the perfect position in a state where there aren't any State Taxes. And as a man who's about as close to retirement as Fitzpatrick is, I'd think it be a factor in any decision to stay or leave.
I do understand his appearent desire to continue to play as a starter. But he needs to realize he may not get a starters role anywhere. He's regressed a bit in 2020 with regard to arm strength and it shows in his choices of where he's throwing the ball, usually the shorter route.
As a fan I'd love to see him return as the main backup.