Have been having problems connecting accounts to GOG for months. Sometimes I dig through forums and find a manual config file edit that works. Sometimes I don't bother. Today I decided to uninstall everything GOG, and delete all GOG and Galaxy folders I could find, and re-download and re-install. Epic, Xbox connect. Origin, Steam, and Ubisoft Connect fail. I haven't tried any others since these 5 are the ones that seem to be there on a fresh install. Why is this so broken? Went from the greatest installer ever to trash in a year. Considering uninstalling again and deleting my account of 5+ years.

If you search the forums you can find temporary fixes for stuff

No one is really maintaining any of this stuff. All the ones you mentioned are 'community' integrations. GOG functionally has washed its hands of these integrations working. Meaning they are broken by design. Because GOG doesn't care.

I mean sure you can find fixes for them, until they break again.

If you want an actual functional and supported centralized client, you might as well use PlayNite. At least the community there cares about the integrations working properly without having to search 100 posts deep into some random forum and trying to figure out which of the 15 'fixes' work.

GOG Galaxy as a centralized game launch platform is fundamentally broken. It will never work. If you want GOG Galaxy for its unique features then use GOG Galaxy for that. But don't use GOG Galaxy as an integrated single game client launcher.