Outsider view.
Right now, Delta wants the 35 RJs to cover the summer because of the way they screwed up with the covid pull down and left the airline under prepared for the comeback.
Soon, Delta won’t need them any more, and their reputation is ruthless. If the 9E pilots overplay their hand in this, they will end up exactly like Comair. This has all happened before. Those who don’t study history are doomed to repeat it.
Endeavor will be shuttered, and Delta will give the RJs to SkyWest and whatever startup they can find to work for bottom dollar. Mark my words.