Ahh, yea. Fighting like SF or MK is a tough one for sure.

Although some might be web-based and not necessarily native to Linux, Itch.io does have a large pool of jRPGs, and the RPGMaker communities have a lot of hidden gems, as well. Might be worth a shot, but there will obviously be some less-than-interesting ones along the way, too. They can't all be zingers.

There's one fairly big rhythm game for Linux that I can't for the life of me remember. I'll try to find it and link, but I think it was posted on Lemmy not too long ago. There's also Clone Hero that might be of interest if you have guitar controllers.

I mean, I get not having a particular loved series in the genre or having older games, but I don't know about being underrepresented as a whole. There's a lot of stuff on Steam.

Like, okay, take fighting games.

Assuming that this list is indeed a complete list of Switch fighting games:

https://www.nintendolife.com/games/browse?system=nintendo-switch&genre=fighting

Then there are 75 fighting games for the Switch.

There are 2,230 games tagged with "Fighting" on Steam.

EDIT: In fairness, some of the stuff tagged as "Fighting" on Steam extends beyond what I'd call the fighting game genre, includes stuff like beat-em-ups, but that's still only partially offsetting the numbers there.