Cannot upgrade Ubuntu 18.04.4

[digital-junkie]

Thank you, I will have to backup my data and run a fresh installation.

[Impavidus]

I hope for you that's all, but I see some random file corruption, which could be an indication of hard drive trouble. You should keep excellent backups at all times. And upgrades don't fix problems (other than driver problems).

FYI, Ubuntu 18.04 comes with both Python 2.7 and Python 3.6. The default is Python 2, because the scripts that need Python 2 don't say so explicitly, whilst the scripts that need Python 3 do say so.