Tbh I'd keep both Chambers and Holding. Both seem integral parts of the squad in terms of having been team members for a very long time, both never caused any turmoil and the biggest criticism you can aim at them is probably being unlucky with injuries and "only" being solid. Holding imo is an absolutely decent backup for a young guy like Saliba, Chambers has honestly impressed me with his latest outing at RB and he can also fill in at CB.
Saliba, Gabriel, Mari, Holding + Chambers is a decent enough CB roster for a domestic only season.
If we didn't have Cedric, Chambers could be a good back-up RB option tbh, offering a different style. But we gave a very stupid contract to Cedric, I think Chambers has to leave simply because there isn't a clear space or role for him here, and we could get maybe 10m from selling him to spend on other players.