Fixing Authentication Error on Login

This issue happens when I trying to using some app, and cannot failed to install it’s dependancies, commplaining about python3, so I uninstalled python3, apt has a promption about bunch of packages will also being removed, I think after I re- install python3, those packages will be back again, which seems not true, before reboot, everything seems all right, I ssh to the machin most of the time, I find it has issue when I want to use RustDesk, after I attach a display to it, there is an Aunthentication Error in the Login screen, and the input text box cannot get focus

The catastrophe emerged on the next boot, my Ubuntu stuck on the followin message:

dev/sda1: clean, xxx/xxxxxx files, xxxxx/xxxxx blocks

Press Alt-F2 and login, then install gnome

sudo apt install gnome