Like someone said above, Toomey probably isn't running again in 2022. I think Lamb and Fetterman will likely run for the seat. I see Shapiro more as running for governor. Some people have mentioned Wolf as possibly running for Senate, but I don't see that happening.
The Republicans should nominate Fitzparick, if he's still around. He has the ability to win over the suburban voters that Toomey won.
Why should one believe Timmy isn't running again in 2022? He's practically a baby by senatorial standards.