Any time I try to install anything or run
apt update, I get this error:
E: The repository 'http://ppa.launchpad.net/armagetronad-dev/ppa/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.
I'm not skilled enough to figure this out. I've seen that I can try ppa purge but I don't know how.