Yeah, 12th gen Framework works basically perfectly. They have a guide for installing various distributions (the one for Fedora is here: https://guides.frame.work/Guide/Fedora+37+Installation+on+th...). Following that, I've been running Fedora 36 and now 37 problem-free, with the only real asterisk being needing to disable brightness-sensing to enable the brightness keys.
I know the 11th gen wasn't quite as smooth, and 13th gen isn't really in people's hands yet (but they are increasingly aware, and supportive, of their Linux-using audience, so I'd be surprised if there were issues). EDIT: Their Linux page does in fact list the 13th gen as being officially supported with Fedora and Ubuntu: https://frame.work/linux
FWIW, even if you don't run Arch, I find that the Arch wiki pages tend to be full of tons of great technical detail, and their page on the Framework backs up the "mostly everything just works" vibe: https://wiki.archlinux.org/title/Framework_Laptop_13
I know the 11th gen wasn't quite as smooth, and 13th gen isn't really in people's hands yet (but they are increasingly aware, and supportive, of their Linux-using audience, so I'd be surprised if there were issues). EDIT: Their Linux page does in fact list the 13th gen as being officially supported with Fedora and Ubuntu: https://frame.work/linux
FWIW, even if you don't run Arch, I find that the Arch wiki pages tend to be full of tons of great technical detail, and their page on the Framework backs up the "mostly everything just works" vibe: https://wiki.archlinux.org/title/Framework_Laptop_13