Not much they can do at this point. They’ve walked themselves into a trap. By getting rid of Joe Biden, Kamala Harris is next in line. And she’s toxic so no one is going to vote for her.
Once they are rid of Biden it is an open convention.
The Party can do as it will do—with obvious risks of course.
But—if the Deep State wants Biden gone—whether that is a wise choice or not—then he is gone.