At this point, there's absolutely no way to predict where people will go or try to go. But what seems a reasonable notion is some will go to other regionals. It's not unreasonable to assume many were already trying to locate elsewhere; now they have to.
The CRJ900 fleet will go to Endeavor and they presumably will need staffing in Atlanta.
And of course part of this story are the CS100s coming to Delta starting next year. That's an increase of capacity at the mainline so they may start hiring.
The question is when will this "future UAL CPA" get signed. Next year? After the current deal in 2023?