There are lots of good resources here https://simracingonlinux.com/

Also the SROL discord (linked from there) is pretty active and helpful.

I have an OpenFFBoard wheel and many many peripherals and all games I’ve tried apart from those that are actively hostile to linux (EA WRC, iracing) work fine. I don’t use sumhub though. From what I understand I guess it does work? https://github.com/srounce/linux-simracing-utils There are also some alternatives but I’m not directly familiar with any of them.

EDIT: Sorry, forgot to clarify that I’m not a Bazzite user, I just use vanilla arch. But I don’t really think there are significant differences when it comes to this. Except if you can’t install some of these tools, in which case you might choose a non-immutable distro since hardware often requires light customization beyond what Bazzite might package.

TIL I’m a savage lol

I like this trend of trying to actually talk to people about things they are working on instead of making assumptions in a vacuum. We could use a little more of that.

Gatgetbridge (your link) has a breakdown of devices they support https://gadgetbridge.org/gadgets/ . You can click through the vendors to find devices which are both “highly supported” and “no vendor-pair”. Meaning most/all the features work without any reliance on the vendor app.

As for the similarity you are asking about with pixel->GrapheneOS, there are very few watches that can run an alternative open source firmware or operating systems apart from the ones that are already open source, like bangle.js, pinetime, etc. Wearables are even more specialized than phones, they require specialized code designed specifically for them and would likely require pretty extreme effort to reverse-engineer.

I use a pebble 2 HR with gadgetbridge but the watch it self runs the old pebble firmware which gadgetbridge talks to. This is fine for me, but if you are looking for a more modern watch you may have to make some compromises.