How I successfully installed ERPNext V13 on Ubuntu 20.04 Virtualbox with Easy Install

Well, it’s installed to ~/frappe-bench
Concerning the upgrade - that didn’t work at all for me, no matter what I tried it was never entirely successful. All I got was one single run that went through despite some errors, but that one gave me another error on login or most of the times when I switched back to the desk. See here: