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.
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.
Im curious why your conception of a warlock must be able to be confused with a wizard or sorcerer from an outside perspective. That has never been an aspect of warlocks in 5e that I valued, or something I particularly wanted to emphasize.
To me, a warlock character could be made using any number of classes present in pf2, including the aforementioned sorcerer, wizard and witch, but also the psychic or oracle. The fantasy of having a patron is not something that must be expressed mechanically IMO, because it ultimately boils down to "you have a connection with this powerful NPC and you need to consider their wants/needs/demands or else there may be consequenses"
Do it! Ive def been there my friend, and i can tell you that it feels good as hell. If you find comfort in "act like youve been there before" then more power to you, but i also think that people should be free to be excited about things! Enthusiasm is great for your self esteem, or at least it is for me!