• https://gitlab.gnome.org/GNOME/mutter/-/issues/1871
• https://gitlab.gnome.org/GNOME/mutter/-/tree/main/src/tests/monitor-configs?ref_type=heads
• https://gitlab.gnome.org/GNOME/mutter/-/blob/main/src/tests/monitor-configs/max-bpc.xml?ref_type=heads (maxbpc)
• https://gitlab.gnome.org/GNOME/mutter/-/blob/main/src/tests/monitor-configs/rgb-range.xml?ref_type=heads (rgbrange)

nano ~/'.config/monitors.xml'

<monitors version="2">
  <configuration>
    <layoutmode>physical</layoutmode>
    <logicalmonitor>
      <x>0</x>
      <y>0</y>
      <scale>1</scale>
      <primary>yes</primary>
      <monitor>
        <monitorspec>
          <connector>HDMI-1</connector>
          <vendor>TCL</vendor>
          <product>55S405</product>
          <serial>0x00000000</serial>
        </monitorspec>
        <mode>
          <width>1920</width>
          <height>1080</height>
          <rate>60.000</rate>
        </mode>
        <rgbrange>full</rgbrange>
        <maxbpc>12</maxbpc>
      </monitor>
    </logicalmonitor>
  </configuration>
</monitors>

sudo cp --remove-destination ~/'.config/monitors.xml' ~gdm/'.config/monitors.xml' && sudo chown 'gdm':'gdm' ~gdm/'.config/monitors.xml'