Democrats may keep control of the Senate in 2022 for one reason:

[lees1975]

6. I don't think any of them are as "vulnerable" as it may seem

Kelly's victory in Arizona was pretty solid, lots more votes than Biden won the state. Warnock will hold on to that seat simply because he will get the turnout from the voters who put him in there in the first place. Hassan and Cortez-Masto aren't as vulnerable as they might want to appear because they need to raise some money.

I do see Democrats picking up the seat in PA vacated by Toomey, and the NC seat that Burr is leaving. Ohio and Wisconsin may be a shade closer but I'd bet odds on the Dems getting one of the two. And I wouldn't be surprised to see a flip in Florida, given who the Democratic nominee may turn out to be.