I agree with your earlier post that Belichick wanted out.
But that's because his power had been eroded badly.
Not only last year, but in previous years as well.
He was submarined by management.
Go back to the poor drafts of '18-20. Think about all the wasted draft picks we made on trades like Sanu or losing Deflategate trades. We were trying to maximize the Super Bowl window. We lost picks to bogus investigations. We sold the future to have one more shot at a Super Bowl. I don't look back with regret, I support it.
So what happens next? Just as the team is starting a total rebuild, the poor drafts of those years puts the owner in the position of stripping some powers from the coach/GM. We're talking about 2021 here. Then coaching decisions are made behind the coach's back. Then finally successor decisions.
The only conclusion is that Belichick was torpedoed by all of this. It's a wonder the players kept playing for him.