You can get an incompetent backup CB for MLS minimum so there’s virtually no point in keeping Zavaleta.
We don’t even have a backup winger. We have Sberg who is young, raw, and probably going to get seriously hurt at some point, and Gallardo who no one has seen play here. That’s why Chapman has been playing in a role he isn’t any good at. Putting Sberg in Chapman’s natural position would probably make him look inept and be a waste, especially since he needs to play if Vanney intends to play a 4-3-3.
You need backup players, and Chapman is good for a few goals or assists when playing in the right spot usually. Even if he hasn’t progressed, likely never will, etc.
The FO would probably gladly ship him off (wouldn’t bother me at all) and replace him with some cast-off USMNT player who won’t be useful either.