Bohuzel repositar neexistuje - Existuje jen repositar pro unstable verzi

Ja tam teda stable vidim :
http://kuiper.mirrorservice.org/sites/trinitydesktop.org/trinity/deb/trinity-sb/dists/jammy/Release

Z 29/04 : http://mirror.ppa.trinitydesktop.org/trinity/deb/trinity-sb/dists/jammy/

Tak si ho jen pridej do /etc/apt/sources.list a zaktualizuj :
deb http://mirror.ppa.trinitydesktop.org/trinity/deb/trinity-sb <your-distribution-release-name> deps-r14 main-r14
deb-src http://mirror.ppa.trinitydesktop.org/trinity/deb/trinity-sb <your-distribution-release-name> deps-r14 main-r14

PS: Me jelo ubuntu 22.04 na gnome 42 svizne na velmi starém HW, mozna jsi mel zvolit jinou verzi s jinou nadstavbou jak instalovat Gnome a to se pak snazit preinstalovavat za KDE, treba Kubuntu 22.04 LTS https://kubuntu.org/news/kubuntu-22-04-lts-released/