I was in a relationship before I started transitioning, but I relate a lot. Not just as transfem, but also because I'm bi. I've never had my gender questioned, but I have most certainly had similar experiences with monosexuals(people who's only attracted to a single gender) due to my sexuality, nearly regardless of which dating space I've been in.

I've only used flatpak and I honestly see no reason to try anything else. The only issue I've encountered is that Steam games launched by the Steam flatpak occasionally act strange (sometimes they can't locate graphics drivers or connect to online services).