Are you really on 20.04.6? The Ondrej repos aren’t maintained for EOL versions of the OS. So, your first problem is either migrating to a server running a maintained OS version or upgrading in place (the former is usually faster and definitely safer than an in-place upgrade).
OK. I didn’t realize it wasn’t supported. So I migrated to 24 something and this problem is solved. Now to open a new thread for the problem this created.