I absolutely understand each of your feelings. The difficulty is that in trying to tell ourselves that we’re not that bad and we can suffer it out we end up stressing our bodies more and bringing us to the point where we are worse off sooner than later. The paradox is that we can’t ever tell if another person sitting needs the seat as much as or more than us. If we can find a way to ask if another person is in need showing compassion in our question it could assist in the matter. Perhaps, “I’m in need, but I would feel badly if someone else who feels like I do or even worse were to have to stand.”
I’ve come across a handful of people with EDS, although not in person that I’m aware of. That certainly doesn’t mean it’s prevalent in the slightest though, that just has to do with the discussion groups I end up being in. I can absolutely relate to not having a specialist. It’s frustrating feeling as though as a patient you’re more of an authority than any of your physicians. They certainly don’t want to feel that way. I’d strongly advise you to find EDS groups online at least for finding recommendations on helpful ways to make your life as manageable as possible. For example I know that many people with EDS have found particular shoes to be incredibly comfortable. Also often times patients group together to advocate for advances for the patient community as a whole, such as specific research and government support.
All my best to you.