The quests demanded an authentication agent, pipewire (whatever that is), some launcher, and amongst others, a clipboard service. After all these things were installed from the terminal, I gave it another reboot. Just to get greeted by the same quest page again, saying the authentication agent is missing. I installed the hyprpolkitagent again via the terminal and pacman. Rebooted again, but no improvement. Somehow it wouldn’t recognize that this package is installed.

Just to check, did you actually enable it? It needs to be run via a exec-once in your hypr config. https://wiki.hypr.land/Hypr-Ecosystem/hyprpolkitagent/