McVay will coach as long as Stafford is a Ram. His skills are the key that unlocks McVay's scheme. With Stafford and Kupp behind a solid OL the Super Bowl showed that everyone knew Kupp was gonna cook and they still couldn't stop Stafford and Kupp. Those two are the core of this offense.
Donald is the core of the defense. When he leaves they still can be good, but he's the one player that can't totally be replaced. I'm thinking 3 years with AD. Stafford is signed through 2026 (5 more years) and IMO that is the minimum Sean will be with the Rams. IMO when Stafford retires so will McVay.
I think Kupp will be extended through 2025 with anything after as void years.