Sam Darnold will probably get the same money as Carr but he might be better. That's likely the only option out there and I'm not sure he's actually better or cheaper.
I do think Carr is probably the best option for next year but no matter how much someone likes Carr, at his age we need to be really aggressive in finding a younger, better QB to replace him.
But, in the end, I think you let your new HC decide what to do at QB. Maybe he like Carr or maybe he wants to get rid of Carr and go with a cheaper but possibly worse vet while developing a young QB.