I may be a touch biased, but I feel like you might enjoy trying Gentoo one day, especially with the recent official binary package host.
IRC is fine, so are mailing lists; I use both, plus various git forges, to contribute to open source projects.
IRC is still going strong on OFTC and Libera.chat
I get that the younger folks like discord, but seriously it’s a proprietary mess that locks everything behind a wall and tries to extract payment from each and every user.
You want a standard rack shelf, it’ll fit 3-4 SFF stacked sideways. You can 3D print some supports.
No idea if it’ll fit in a shallow rack.
Dynamically linked all the way; you only have to update one thing (mostly) to fix a vulnerability in a dependency, not rebuild every package.
Yeah they’ve only rolled out a version of curl that broke the package manager a few times.