Everyone's upgradable except for the best player at each position in the league (and I guess that's debatable too). So he's def upgradable and since I consider him to be good in this system but not great, I think if the price is right we can find an upgrade next year.
I just don't generally think center needs to be where premium capital is spent but every offseason is a different animal.
As to this moment: I don't see a scenario where we upgrade him ahead of 2026 season and depending on factors that can't be fully known at this time, I would not be opposed to bringing him back on a decent contract for two more seasons. But many things need to play out: draft scouting of centers, player development here, a contract hopefully at one of the guard spots, etc... before I'd make a decision.
At the end of the day - It's just not a position I find worth banging the drum for a top 10 player at but I'll be happy if circumstance brings us one there.