I’ll be honest, I’m extremely picky about how I like my gofushi! 😅 So it’s not something I really seek out, but if I see a doujin that looks interesting with them, I’ll definitely read it lol.
I don’t really see them being romantic with each other (since I don’t think Megumi would reciprocate, and I don’t think Satoru would let himself be completely vulnerable around him), but there’s a couple of scenarios I’ve found interesting?

// sexual assault+underage, past Tojigo
-Anything where Satoru has a fixation on Megumi based on his trauma with Toji (especially if it’s because Toji assaulted him). Basically, he doesn’t “see” Megumi at all, he’s just a stand-in for Satoru to reclaim his sense of control, and all he sees is Toji’s image in his face. Since it would have started when Megumi was pretty young, I imagine he would have accepted it after a while? Kind of like “This is just what I have to do to keep Tsumiki safe,” so I don’t think he’d actively hate or try to escape the situation, either. He’d just see Satoru as this guy that pays for his shit, breathe heavily on his face, say weird shit, and touch his dick. I’d be curious to know how someone like Yuuji or Nobara would react when they found out.

-I remember reading a doujin where the Gojo and Zenin clans force an arranged marriage between the two, and I think there’s a lot of potential with this premise. A big part of JJK to me is the contrast between the old and modern worlds, the clan system being a remnant of the former. I mean, it would just make sense for two of the biggest clans to want a marriage between the two, right? Consolidate power and all that. I think what makes these two good candidates to explore this, is that I can’t really see them falling in love with each other? Just like real political marriages, they are forced together through circumstance, and now they have to find a way to operate despite personality tensions. Is it possible to love someone in a situation like this if you’re not attracted to them? Should you rebel against the system and put someone in danger who is just as much a victim as you are? How would an open relationship work out in a clan/court setting like this? How do you enjoy something (sex) if every fiber of your body resists it?
Anyways, I think it’d be an interesting subversion of the trope, and it’d be very awkward and very painful to read 👍

tl;dr I don't like gofushi often, but if I do, the themes I like to explore are dissociation and physical relationships that exist outside of conventional romantic love.