I don't see Rodon coming back to the Sox. Next season you have the following four pitchers as near locks to be in the rotation:
Also, Keuchel is still under contract next season and it would be difficult to move him in a trade, given his performance and salary for 2022. The Sox are unlikely to let Keuchel reach 160 innings in 2022, as that would vest his option for 2023. To avoid that, we'll probably see Reynaldo Lopez get a fair amount of starts, which he has earned to this point.
Carlos has been excellent this season. Let's ride him to a World Series win and offer him the QO. He'll get a well-deserved payday from another team and the Sox will get a comp pick.