If I were them, I'd offer him a lengthy deal at somewhat low franchise QB money (probably at like $20-25M a year). That's not going to cripple the franchise at these cap values. If he doesn't like it, he can leave, and I don't think he'll find a strong market in a range above that league-wide. He'll land a starting gig for good money, but I don't see any team paying him above $30M a year at this point.
Cleveland is in a spot with a lot of teams, like Buffalo (not anymore, but before Allen), Jets, Dolphins and a few others, where they don't really have the luxury of being "picky" about their QB. If they manage to draft somebody who's at least competent, I wouldn't be so quick to move off of them just because they're not Brady or elite.
People need to realize some of these franchises have seen multiple decades go by without franchise-level QB play. Baker is probably the best Browns QB they've seen in like 20 years or more. It's a low bar to achieve, but the point being that they've whiffed a TON on QBs, and its not super easy to just say "well he's not great, so lets move on and try again". They could end up with the next Peyton Manning, or the next Mark Sanchez. There's just no way to know.