You could try Fetlife! Its not a dating app specifically, but rather a kink focused social network/forum. You can find communities for your area and interests, and a lot of people on there are poly.

Sandshrew is the best Pokémon because they are non-binary and autistic coded. I will not be taking any further questions.

Its this community! You are already in the right place!

I was in a similar spot at the beginning of my transition. Visible M and thinning up to a few inches back. I am now just over a year on HRT and my hairline has improved significantly. I still have the M, but its much less pronounced and the thin parts are filling back in nicely.

I also had major dysphoria about my hairline, but now its way better and I barely think about it anymore. The way it works as far as I understand is that damaged hair follicles will repair themselves but destroyed follicles will stay destroyed. When you start T blockers the damage should stop getting worse right away and then begin to recover slowly over time.