It’s Arch and Arch-derivatives. And I’m saying it as an Arch user, btw, and I actually love it.
Between the Big Three (Fedora, Debian, Arch), it is the least likely to have an official package for somewhat niche applications. If something is not available as a flatpak or appimage, I have to compile it from source or an AUR PKGBUILD, but we all know the dangers of doing that. Some software will just assume that it’s running on a particular disribution, usually Ubuntu. Some software will detect the distribution and straight-up refuse to work on Arch.
That being said, it would take a lot to make me switch to a stable point-release distribution. Arch’s advantages more than make up for the sub-par software support.
(actually, I lied. Fuck Canonical and *Ubuntu. And IBM.)