It does need regular maintenance, as highlighted in every single stable update announcement.
If you’re talking about “Known issues and workarounds” those aren’t caused by Manjaro, they’re issues that crop up with various packages. The forum attempts to crowdsource fixes as part of Manjaro’s mission to make it easier on its users.
It’s a great resource and it can be used by people on any Arch-related distro (and potentially other distros as well). I wish more distros would do this.
It is absolutely not stable (as in Debian Stable or RHEL or SLES stable) as things are moving quickly.
Well it’s still a rolling distro with Arch heritage. It’s as stable as you can make Arch. Which is quite stable in the sense that a Manjaro install won’t stop working out of the blue (I can attest to that personally, going on the 5th year as a daily driver). And they’ve gone and added Timeshift snapshots as default so if you mess something up you can simply restore a snapshot, which takes care of user-related tinkering as well.
Okay, almost-semi-regular then.
Not sure I understand your point about the updates (or the “almost-semi” thing). What does it matter if updates come after 13 or 17 days? Is it important to you to be exactly 14 or what?
AUR creators, on the other hand, are overwhelmingly Arch users who builds their scripts targeting an up-to-date Arch system.
10% of AUR packages are abandoned. Another 20% have never been updated after the initial release. Only 35% have been updated within the last year.
Anyway, it doesn’t matter. AUR “packages” are recipes that either compile packages from source or download binary releases. Both methods are very resilient and don’t care about delays of a couple of weeks.
While you can in theory run into an AUR package that was just updated to require something that was just added to Arch the chances are extremely small. It’s hardly a common problem.