I don’t have a ton of experience with Windows lately, but from trying to troubleshoot family members’ PCs, it usually ends up being corrupted drivers or bricked bootloaders/failed updates.
As for documentation, the Arch wiki (and Gentoo wiki, Debian wiki, etc. etc.) is usually a good source of information for general topics, but there’s also decades of forums and stackexchange posts on various problems if you’re just using a search engine. Every program also has extensive official man pages on how to use them (example), and you can even use something like tldr to shorten the man pages into something usable right now (example). If you’re willing to read documentation, everything you use on Linux probably has a manual behind it.
With regards to paying for support, it’s not really my wheelhouse but to my understanding that’s what companies like Canonical, SUSE, and Red Hat offer.