I believe I might’ve found the culprit; Having checked “Install NDIVIA Drivers” [SIC] on RC1 and forwarding my Nvidia GPU on my Jellyfin container, it appears to have ve potentially stopped the app-system from initiating properly.
It would seem Nvidia drivers may be installed per boot-environment, and when upgrading, therefore may not be present on the new boot environment when a user upgrades their system, despite it’s checkbox still being checked.