I will admit that I find the "they are teammates and that's
all that matters" thing amusing. That's true in the lower levels. When you get into the higher levels, and it becomes all about college scholarships and all the opportunities that come from being a high performer, and I hear "Well, it's cut throat and competitive. All bets are off." And information is power. No one seems to flinch much at that. But at that point, it just is and you're used to the competitiveness, I guess.
The truth is somewhere in the middle. Absolutely yes, they are teammates and need to be supportive of each other. And each of them needs to be focused on themselves and their growth because if they aren't, no one else will be. But at this point, that just means focus on being healthy, working hard in gym, and training mental toughness.
I'm also not going to fault you:
I guess they've made it clear who their priority is
Yes. They have. For right now. That's their prerogative. If your daughter had scored .3 higher and been 2nd or 1st, she would have been the one emphasized, but would you have said "I guess now my girl is the priority"? Probably not.
This is the sport, OP. Your girl may never be on top again. Jess may have a few good years and then be replaced as highest performer, or she may continue to grow quickly. A new girl may come in. Someone who is currently scoring lower might suddenly take off. Who know? But you have to see that all the distress this has caused you just can't continue through a long gymnastics career. Do you really want to feel like this and do this every day for the next 10 years?
I'm also concerned for you in another way. I REALLY hope, for your sake, that you changed some of the details here. Changed names. You probably didn't change dates. It wouldn't be too hard, I'm guessing, to figure out who you really are, particularly for someone who knows you. I understand that you are just trying to find some support.. you've acknowledged that you know you need to back down.. but someone you know is going to read this stuff. I can't imagine the drama when some of this hit the fan. Coaches don't really take well to being accused of favoritism. Some gyms bristle when questioned about their choices. This could damage your and your daughter's relationship with the rest of the team. I REALLY REALLY hope you've been careful who, how, and when you have vented about this.