My gnome terminal won't open. I tried uninstalling and reinstalling it. No luck. I was able to install an Xfce terminal though. There is also a red circle with a white x on it in the lower right hand corner of my machine.
This is the error message I get:
The repository 'http://ppa.launchpad.net/bluetooth/bluez/ubuntu focal Release' does not have a Release file.
Updating from such a repository can't be done securely, and is therefore disabled by default.See apt-secure(8) manpage for repository creation and user configuration details.
The repository 'http://ppa.launchpad.net/embrosyn/cinnamon/ubuntu focal Release' does not have a Release file.
Updating from such a repository can't be done securely, and is therefore disabled by default.See apt-secure(8) manpage for repository creation and user configuration details.
Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi'Sub-process returned an error code
No matter whether I update, upgrade, etc. run other commands in the terminal, that doesn't seem to work. I've tried some of the other solutions for similar errors on this site and that also has not worked. I cannot use zfs snapshot because I don't have that setup for this machine either.
UPDATE: While trying to remove the PPA I ran into issues doing so, as the comments show. A comment which is now deleted, suggested looking here for answers: "ModuleNotFoundError: No module named 'apt_pkg'" appears in various commands however, while trying to implement what was shown there, it resulted in my keyboard and mouse no longer being usable once I am at the login screen. I then tried to reboot in safe mode and try repairing the machine that way with various procedures and commands (since my keyboard was usable there, just not at the login screen. None of the attempts to repair the system were successful.
As a last resort, I am going to create a live Ubuntu instance on a USB and see if I can do any data recovery that way, to an external drive, then reinstall the operating system.
