AUR may not be perfect but there is very little software out there that someone hasn’t already packaged in it and it’s a great deal more convenient to use than faffing with custom repos.
The Arch Wiki is second to none too. I’ve even occasionally found myself using it when debugging other Linuxes.
I definitely wouldn’t use Arch on a server though. I mean, I have done, multiple times in fact, but they’ve always been personal systems. I much prefer FreeBSD for servers. Professionally it has usually been Debian, CentOS, or, much more recently, Ubuntu Server (but I really don’t like Ubuntu Server. Or Desktop for that matter).
Disclaimer: this is all my own opinion and I’m not trying to pass any of it off as fact.
More like the reverse, the Arch Wiki is the best so everyone uses it. Although for some topics it makes sense to take a look at Debian or Gentoo wikis, too.
Not sure what other kind of 'Debian resources'/assets you had in mind.
What do you mean by "programs usually tailored for Debian", in general Linux programs for sure won't be tailored for Debian, except for Debian-internal developer tools perhaps.