Failed to start GNOME Shell ox X11

This issue happens on a desktop PC running Ubuntu 20.04.

Yesterday, 07/22, I ran an update and installed the following:

facundo@razorback:~$ awk '$1=="2020-07-22" && $3=="upgrade"' /var/log/dpkg.log
2020-07-22 13:22:48 upgrade base-files:amd64 11ubuntu5 11ubuntu5.1
2020-07-22 13:22:52 upgrade python3.8-dev:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:52 upgrade libpython3.8-dev:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:53 upgrade libpython3.8:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:54 upgrade python3.8-venv:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:55 upgrade python3.8:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:56 upgrade libpython3.8-stdlib:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:57 upgrade python3.8-minimal:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:58 upgrade libpython3.8-minimal:amd64 3.8.2-1ubuntu1.1 3.8.2-1ubuntu1.2
2020-07-22 13:22:59 upgrade libpulse-dev:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:00 upgrade libpulse-mainloop-glib0:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:01 upgrade libpulsedsp:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:01 upgrade pulseaudio-utils:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:02 upgrade pulseaudio-module-bluetooth:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:03 upgrade pulseaudio:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:05 upgrade libpulse0:amd64 1:13.99.1-1ubuntu3.4 1:13.99.1-1ubuntu3.5
2020-07-22 13:23:08 upgrade ubuntu-drivers-common:amd64 1:0.8.1.1 1:0.8.4~0.20.04.1
2020-07-22 13:23:09 upgrade sudo:amd64 1.8.31-1ubuntu1 1.8.31-1ubuntu1.1
2020-07-22 13:23:11 upgrade ubuntu-release-upgrader-gtk:all 1:20.04.21 1:20.04.23
2020-07-22 13:23:12 upgrade ubuntu-release-upgrader-core:all 1:20.04.21 1:20.04.23
2020-07-22 13:23:13 upgrade python3-distupgrade:all 1:20.04.21 1:20.04.23
2020-07-22 13:23:13 upgrade evince-common:all 3.36.5-0ubuntu1 3.36.7-0ubuntu1
2020-07-22 13:23:15 upgrade evince:amd64 3.36.5-0ubuntu1 3.36.7-0ubuntu1
2020-07-22 13:23:17 upgrade libevdocument3-4:amd64 3.36.5-0ubuntu1 3.36.7-0ubuntu1
2020-07-22 13:23:18 upgrade libevview3-3:amd64 3.36.5-0ubuntu1 3.36.7-0ubuntu1
2020-07-22 13:23:19 upgrade libnss3:amd64 2:3.49.1-1ubuntu1.2 2:3.49.1-1ubuntu1.3
2020-07-22 13:23:20 upgrade evolution-data-server:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:21 upgrade libcamel-1.2-62:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:21 upgrade evolution-data-server-common:all 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:22 upgrade libedataserver-1.2-24:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:23 upgrade libecal-2.0-1:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:24 upgrade libedata-cal-2.0-1:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:25 upgrade libebook-contacts-1.2-3:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:26 upgrade libedata-book-1.2-26:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:26 upgrade libebackend-1.2-10:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:27 upgrade libebook-1.2-20:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:28 upgrade libedataserverui-1.2-2:amd64 3.36.3-0ubuntu1 3.36.4-0ubuntu1
2020-07-22 13:23:28 upgrade mutter-common:all 3.36.3-0ubuntu0.20.04.1 3.36.4-0ubuntu0.20.04.1
2020-07-22 13:23:29 upgrade gir1.2-mutter-6:amd64 3.36.3-0ubuntu0.20.04.1 3.36.4-0ubuntu0.20.04.1
2020-07-22 13:23:30 upgrade libmutter-6-0:amd64 3.36.3-0ubuntu0.20.04.1 3.36.4-0ubuntu0.20.04.1
2020-07-22 13:23:31 upgrade im-config:all 0.44-1ubuntu1 0.44-1ubuntu1.1
2020-07-22 13:23:32 upgrade libfprint-2-2:amd64 1:1.90.1+tod1-0ubuntu4 1:1.90.2+tod1-0ubuntu1~20.04.1
2020-07-22 13:23:33 upgrade libfprint-2-tod1:amd64 1:1.90.1+tod1-0ubuntu4 1:1.90.2+tod1-0ubuntu1~20.04.1
2020-07-22 13:23:34 upgrade linux-firmware:all 1.187.1 1.187.2
2020-07-22 13:23:45 upgrade simple-scan:amd64 3.36.0-0ubuntu1 3.36.3-0ubuntu0.20.04.0
2020-07-22 13:23:47 upgrade yaru-theme-gnome-shell:all 20.04.7 20.04.8
2020-07-22 13:23:48 upgrade yaru-theme-gtk:all 20.04.7 20.04.8
2020-07-22 13:23:49 upgrade yaru-theme-icon:all 20.04.7 20.04.8
2020-07-22 13:23:53 upgrade yaru-theme-sound:all 20.04.7 20.04.8
2020-07-22 13:23:54 upgrade mutter:amd64 3.36.3-0ubuntu0.20.04.1 3.36.4-0ubuntu0.20.04.1

After that, whenever I turn the monitor off an on again I'm greeted with a blank screen and the message:
"Oh no! Something has gone wrong.
A problem has occurred and the system can't recover.
Please log out and try again."

I'm able to log-in again but the problem persists. Every time I turn on the monitor, the same happens.

So I reproduced the problem and found this on syslog:

Jul 23 11:23:40 razorback gnome-shell[6832]: **
Jul 23 11:23:40 razorback gnome-shell[6832]: mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:40 razorback gnome-shell[6832]: Bail out! mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:40 razorback gnome-shell[6832]: GNOME Shell crashed with signal 6
Jul 23 11:23:40 razorback gnome-shell[6832]: == Stack trace for context 0x5605f4678700 ==
Jul 23 11:23:42 razorback systemd[2371]: gnome-shell-x11.service: Main process exited, code=dumped, status=6/ABRT
Jul 23 11:23:42 razorback systemd[2371]: gnome-shell-x11.service: Failed with result 'core-dump'.
Jul 23 11:23:42 razorback systemd[2371]: gnome-shell-x11.service: Scheduled restart job, restart counter is at 1.
Jul 23 11:23:42 razorback systemd[2371]: Stopped target GNOME X11 Session (session: ubuntu).
Jul 23 11:23:42 razorback systemd[2371]: Stopping GNOME X11 Session (session: ubuntu).
Jul 23 11:23:42 razorback systemd[2371]: Stopped target GNOME X11 Session.
Jul 23 11:23:42 razorback systemd[2371]: Stopping GNOME X11 Session.
Jul 23 11:23:42 razorback systemd[2371]: Stopped target GNOME Shell on X11.
Jul 23 11:23:42 razorback systemd[2371]: Stopping GNOME Shell on X11.
Jul 23 11:23:42 razorback systemd[2371]: Stopped GNOME Shell on X11.
Jul 23 11:23:42 razorback systemd[2371]: Starting GNOME Shell on X11...
Jul 23 11:23:45 razorback /usr/lib/gdm3/gdm-x-session[6713]: (II) event5 - Logitech G403 Prodigy Gaming Mouse: SYN_DROPPED event - some input events have been lost.
Jul 23 11:23:46 razorback gnome-shell[21905]: **
Jul 23 11:23:46 razorback gnome-shell[21905]: mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:46 razorback gnome-shell[21905]: Bail out! mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.service: Main process exited, code=dumped, status=6/ABRT
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.service: Failed with result 'core-dump'.
Jul 23 11:23:46 razorback systemd[2371]: Failed to start GNOME Shell on X11.
Jul 23 11:23:46 razorback systemd[2371]: Dependency failed for GNOME Shell on X11.
Jul 23 11:23:46 razorback systemd[2371]: Dependency failed for GNOME X11 Session.
Jul 23 11:23:46 razorback systemd[2371]: Dependency failed for GNOME X11 Session (session: ubuntu).
Jul 23 11:23:46 razorback systemd[2371]: <email address hidden>: Job <email address hidden>/start failed with result 'dependency'.
Jul 23 11:23:46 razorback systemd[2371]: gnome-session-x11.target: Job gnome-session-x11.target/start failed with result 'dependency'.
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.target: Job gnome-shell-x11.target/start failed with result 'dependency'.
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.service: Scheduled restart job, restart counter is at 2.
Jul 23 11:23:46 razorback systemd[2371]: Stopped GNOME Shell on X11.
Jul 23 11:23:46 razorback systemd[2371]: Starting GNOME Shell on X11...
Jul 23 11:23:46 razorback gnome-shell[21946]: **
Jul 23 11:23:46 razorback gnome-shell[21946]: mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:46 razorback gnome-shell[21946]: Bail out! mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.service: Main process exited, code=dumped, status=6/ABRT
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.service: Failed with result 'core-dump'.
Jul 23 11:23:46 razorback systemd[2371]: Failed to start GNOME Shell on X11.
Jul 23 11:23:46 razorback systemd[2371]: gnome-shell-x11.service: Scheduled restart job, restart counter is at 3.
Jul 23 11:23:46 razorback systemd[2371]: Stopped GNOME Shell on X11.
Jul 23 11:23:46 razorback systemd[2371]: Starting GNOME Shell on X11...
Jul 23 11:23:46 razorback gnome-shell[21961]: **
Jul 23 11:23:46 razorback gnome-shell[21961]: mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:46 razorback gnome-shell[21961]: Bail out! mutter:ERROR:../src/backends/x11/meta-monitor-manager-xrandr.c:211:meta_monitor_manager_xrandr_update_screen_size: assertion failed: (width > 0 && height > 0 && scale > 0)
Jul 23 11:23:47 razorback systemd[2371]: gnome-shell-x11.service: Main process exited, code=dumped, status=6/ABRT
Jul 23 11:23:47 razorback systemd[2371]: gnome-shell-x11.service: Failed with result 'core-dump'.
Jul 23 11:23:47 razorback systemd[2371]: Failed to start GNOME Shell on X11.
Jul 23 11:23:47 razorback systemd[2371]: gnome-shell-x11.service: Scheduled restart job, restart counter is at 4.
Jul 23 11:23:47 razorback systemd[2371]: Stopped GNOME Shell on X11.
Jul 23 11:23:47 razorback systemd[2371]: gnome-shell-x11.service: Start request repeated too quickly.
Jul 23 11:23:47 razorback systemd[2371]: gnome-shell-x11.service: Failed with result 'core-dump'.
Jul 23 11:23:47 razorback systemd[2371]: Failed to start GNOME Shell on X11.
Jul 23 11:23:47 razorback systemd[2371]: gnome-shell-x11.service: Triggering OnFailure= dependencies.
Jul 23 11:23:47 razorback systemd[2371]: Started GNOME Session Failed lockdown screen (user).
Jul 23 11:23:47 razorback systemd[2371]: Reached target GNOME Session Failed.
Jul 23 11:23:47 razorback systemd[2371]: Condition check resulted in Disable GNOME Shell extensions after failure being skipped.

Before the upgrades, I had no problems at all.

Thanks in advance. This is my first post, so please excuse my lack of technical knowledge.