I don’t think the Sox could trade Eovaldi without having some good blackmail. He’s owed too much and simply not durable.
Devers looks like a building block. Sure the Sox could arguably get more for him than anyone else, but in any trade of a marquee piece, you’re hoping to get a controllable asset you can build around, which Devers already is. So why trade Devers when you’re hoping to get someone like Devers back?
JDM has the most uncertain future on the team. The smart move might be to negotiate an extension with a lower AAV but more years...