> The point of the Framework is to run Linux
Until recently they've been almost as second-class-Linux-to-Windows as say Dell, but perhaps you just meant 'non-macOS'?
(For example, I'm currently struggling to get my early-days pre-ordered 11th gen Intel BIOS updated from v3.07 without a) the official Windows updater; b) modifying the supplied firmware on the instruction of AI or stranger third-parties in unmerged PRs/GH issues.)
I'm just one datapoint, but my Framework 16 (bought a little over a year ago with no OS, has only ever had Linux installed on it) has never given me trouble with firmware updates. I've updated the BIOS twice, and other firmware, all through `fwupdmgr` with no issues. I bought the AMD chip rather than Intel, it's possible that that was why I had no issues, but I don't actually know.
I'd call that pretty recent :) – fwupdmgr wasn't supported (not as in 'you're on your own', but 'blobs not published to registry') until a few years ago. EFI shell update wasn't available early on. When I say I'm trying to, I'm actually struggling to establish if it's even possible without at least using Windows to jump to a certain version after which I can use EFI/fwupdmgr.