You can't have a full desktop with just GNU packages as X11 it's MIT licensed, but it's fine.

Also, on Texinfo, it lies on Texlive for PDF's and HTML math output, but by default tlmgr (the texlive installer) will install a full set just composed of FLOSS (DFSG) licensed packages, enough to cover a 99,999% of the real life Texlive usage.

Back to desktop environments, I don't consider GNOME part of GNU any more, they even promoted propietary software being readily available through flatpak under their blog.

Gnome became RedHatware, or Icazaware. And, sadly, GNUStep went somewhere out from GNU. I think I heard that from Gregory Casamento, but I might be wrong.

Said this, even if GNUStep looks outdated, it would have been a far better way than Gnome, which broke everywhing with every release to be a platform for RH/SystemD and nothing more.

GNUStep would have several options to run fast on both legacy and modern machines. Maybe you don't know, but it has modernish themes looking better than the squared NeXT look.