The system is called GNU/Linux: https://www.gnu.org/gnu/linux-and-gnu.html
Parabola GNU/Linux basically is Arch without the proprietary software. Since
you wrote that you had a good experience with Arch, you should be at home.
Trisquel is based on Ubuntu: fixed instead of rolling release,
You can easily use Trisquel with a recent Linux-libre kernel thanks to
jxself's great work: https://jxself.org/linux-libre/
iTunes and Spotify mean proprietary software, DRM, snooping, censorship, etc.
About Apple (including iTunes): https://stallman.org/apple.html
About Spotify:
Hi and welcome lodonnell921
grsecurity is a set of patches under GPL V2, a way to test how this behaves
with a Linux-Libre Kernel is with
https://heads.dyne.org/about.html ;-)
