[tmottabr]

You should be able to upgrade without any hacks.

21.10 reaching EOL just means that it stopped receiving updates, everything else should still work as is.

Just install the update-manager-core and run "do-release-upgrade -d" as sudo.

[sexy_panda]

Well this didn't work, but this worked / is currently running:

https://fedingo.com/how-to-install-or-upgrade-software-from-...