I read your post yesterday but didn't reply because I doubted I had anything to offer of any consequence. However, at this point, since no one has replied to your post I thought I would. In my case, I don't have any friends. So... no... I've never had any friends who talk about their fetish constantly... or anything else for that matter.

I noticed, however, that you mentioned you have really bad gender dysphoria. And this is something I'm all too familiar with. I'm an older person now. But gender identity has been a lifelong struggle for me. And even now, at this late stage in my life, I still feel an almost overwhelming need to talk about it.

A few years ago, I got to know several YouTubers who were transitioning (MtF). And being involved with them gave me an outlet. However the little MtF trans community that existed on YouTube at the time has pretty-much gone by the wayside now. So I no longer have anyone to talk to & I just keep it all to myself.

From my perspective, I think the situation you describe is a matter of boundaries. You simply have to decide (as it sounds like you have) what you can & can't tolerate, communicate those limits, & enforce them. (There are lots of internet articles on the subject of boundaries, as well as videos on YouTube. Family therapist Kati Morton has one.) And, of course, in turn, as you already realize, you must reciprocate by not discussing your own issues.

The problem with this, of course, is that it closes off one opportunity you have to talk about your gender identity issues. Hopefully you have others. (Perhaps you're transitioning or at least receiving some gender-identity-related therapy?) But, if not, I hope you will try to figure out some other way of talking about your trans issues. Because I know, from personal experience, how difficult it is to just keep it all bottled up. I wish you well...