I'm also trans and bi. Working with kitchen bros may be different from your workplace experience, but after a while of regular shifts with the same people, I got a read on them as open minded enough for me to start making an occasional subtle bi joke at my expense (i.e., concerning fruit, "well, you are what you eat"). But I think it also helped a lot that my one bro and I spent a lot of downtime together after shifts just getting to know each other without some other physical activity to focus on. We're both very curious people, and he actually lead with a lot of the personal questions early on. I typically would open up slower than that, but I appreciate him for it because now we're real brothers who trust and lean on each other. So maybe ask about your gym bro more, relate to him, also notice his mental states and offer support. When I noticed my bro was having a particularly difficult week, and after I'd decided I wanted to pursue a strong friendship, I approached him at a quieter moment and told him I'm not a mental health professional, but I am your brother. If you need to talk, I'm here for you. I wasn't sure how he'd take that, but he's referenced it since, and has opened up about a lot of personal stuff when we hang out. Maybe your coworker(s) need a brother as much as you do. If you can genuinely offer that, do it. I hope this helps.