You are correct, this is Michael´s last episode. The actor got fired and David is a casualty of that and is gone too.
Michael´s actor is anti vax, Covid restrictions got stricter, he refused to take the vaccine = he got fired. And then he tried to sue Fox, so yeah... chances of him coming back, even with the change to ABC later on are very slim. Unless they recast him. But, slight spoilers, so far he hasn´t shown up again
At least he got a nice send off.
All the little stories within the hospital were really great, I especially liked Rupert. And I think the thing that affected Ravi was that Rupert pushed him out of the way and saved him, as well as the relating to him with the cancer, which they just really casually thrown out there as Ravi´s backstory