If they'd have to eat a bunch of his salary or give up a pick or something it's really not worthwhile. I do think part of his issue early on last year was the lack of work with Stafford in the offseason/camp and the OL issues which resulted in Stafford locking onto Kupp
way too much.
Like you said he's not going to be a 1,000-yards guy but if he can pick up where he left off (21 catches, 72% catch rate and 2 TDs in his last 5 games) he can be a productive asset in this offense. Having Jefferson with them would help too.
They can cut ties way more cleanly in 2024 if they want ($10.1M cap saved).