More than happy to accept any human being changing with me. In some European countries most changing rooms are unisex.
Aside from schools, I do not really understand the changing room battle (from either side).
No adult really has to use a changing room at all and most swimming pools have cubicles. As for gyms, I would consider these luxury items and you can join one that caters to what you want (provided you can afford it). You can also go changed and shower at home.
Personally I think gyms should be free to set their own policy re trans. That way you could get single sex only, single ‘gender’ only (I don’t really believe in that either) and unisex. People could choose their gym according to their belief.
And if women decamped en masse from single ‘gender’ and unisex, those gyms would cease to exist.
There is surely a market (if these boards are anything to go by) for a female sex only gym.