На второй консоли можно выполнить вход в систему в текстовом режиме. По журналу фэйлит некий prefdm.service
upd. руками запустился lightdm.
$ systemctl status prefdm.service
● prefdm.service - Display Manager
Loaded: loaded (/lib/systemd/system/prefdm.service; disabled; vendor preset: disabled)
Drop-In: /lib/systemd/system/display-manager.service.d
└─plymouth-quit.conf
Active: failed (Result: exit-code) since Wed 2019-10-30 10:34:16 +04; 17min ago
Process: 2464 ExecStart=/etc/X11/prefdm -nodaemon (code=exited, status=1/FAILURE)
Main PID: 2464 (code=exited, status=1/FAILURE)
окт 30 10:34:16 notebook.localdomain systemd[1]: prefdm.service: Service has no hold-off time (RestartSec=0), scheduling restart.
окт 30 10:34:16 notebook.localdomain systemd[1]: prefdm.service: Scheduled restart job, restart counter is at 5.
окт 30 10:34:16 notebook.localdomain systemd[1]: Stopped Display Manager.
окт 30 10:34:16 notebook.localdomain systemd[1]: prefdm.service: Start request repeated too quickly.
окт 30 10:34:16 notebook.localdomain systemd[1]: prefdm.service: Failed with result 'exit-code'.
окт 30 10:34:16 notebook.localdomain systemd[1]: Failed to start Display Manager.