@celesteh I can't actually get 20.10 to upgrade to 21.04 and I've had similar issues in the past so I usually just do a clean install.
I've found that backups are a lifesaver for me, and I've written a very crude shell script that I run after restoring my data that reinstalls most of my preferred apps/snaps, including adding a repository or two.
That alone is a massive time saver. Good luck!
@BustaMarx @celesteh I haven't tried an upgrade to a new distro version in a decade or so and have just got used to clean installs. If you have disk space it might take less than an hour - make a new partition for the install, install keeping the old partitions, and copy over stuff you need as you need it. Personally I find default linux configurations are so good these days that I need to do very little to get things how I like them.
We are a Mastodon instance for LGBT+ and allies! ☺