Hello you might read this link.
https://www.linuxtechi.com/upgrade-ubuntu-20-04-to-ubuntu-22-04/
I was on Ubuntu MATE 20.04 and followed instructions and ended up with Ubuntu MATE 22.04. All went well for me, actually did try live DVD / USB just to verify one of my critical programs worked. After upgrade just lost one minor not used program not in repository. All my other programs ported over and seems like Thunderbird works better for me. Note elsewhere Firefox is now a snap but if not desired there is post on options.
https://ubuntu-mate.community/t/firefox-installation-guide-non-snap/25299/19