I've lost everything and I don't know how to get it back. How can I repair my system all I have is a usb with slax linux. I am freaking out because I had a lot of projects on their that I hadn't pushed to github as well as my configs and rice. Is there any way to repair my system? Can I get a shell from systemd?
Other people will probably give you better answers, but I think the solution is quite easy: chroot and relauch the update.
Pretty much all the other answers are coming down to this, yeah.