Some of the most gut-wrenching body swap stories I've stumbled upon lately are actually in the indie queer romance scene on platforms like Radish and Tapas. They'll set up a typical trope—magic, freak accident, whatever—but then completely twist it to explore gender dysphoria or the raw vulnerability of being physically seen in a body that doesn't feel like your own.
There's one story, I can't recall the exact title, where a trans man and a cis woman swap. It wasn't played for cheap laughs at all. Instead, it dug into his grief at losing his hard-won physicality and her sudden, overwhelming confrontation with male privilege. The spicy elements came from this intense, awkward intimacy of having to guide each other through basic bodily functions, which built a crazy-deep emotional bond. The physical tension was all about navigating this new interface, not just random lust.
I find the apps themselves are hit-or-miss for searching, though. My method is to find one good story with the tag and then check the author's 'following' list. You often find these brilliant, emotionally dense tales hiding in plain sight, written by authors who are clearly working through something very personal.