Dual Monitors not using DPMS with screensaver

Question

Settings -> Power -> Blank Screen set to 1 minute

Ubuntu 20.04 21.10, fresh install, that is now updated to 22.04. Dual monitors, one connected via HDMI, the other via DVI. After a minute, both monitors slowly fade to black. Then one monitor goes into standby. When the other monitor goes into standby, the first one powers back up and then the other powers up. Both screen remains black, though, with only their backlighting and the mouse pointer visible.

$ xrandr -q
Screen 0: minimum 320 x 200, current 3600 x 1080, maximum 16384 x 16384
HDMI-A-0 connected 1680x1050+1920+0 (normal left inverted right x axis y axis) 474mm x 296mm
   1680x1050     59.95*+
HDMI-A-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080     60.00*+  50.00    59.94  
DisplayPort-0 disconnected (normal left inverted right x axis y axis)

$ xset q
Screen Saver:
  prefer blanking:  yes    allow exposures:  yes
  timeout:  0    cycle:  0
DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Enabled
  Monitor is On

It looks like this may be an ongoing issue with multi monitor setups. A review of some of the relevant questions:

• Monitors do not turn off (enter powersave mode) after screen blanking

proposes a workaround solution to disable the auto input select option on the monitor. My HDMI monitor does not contain such an option to disable, so sadly this is a no-go.

• How do I enable console blanking and display power save on a laptop server install?

suggests using setterm on an Ubuntu Server installation. This command returned an error. I suspect it isn't relevant to desktop installations.

• Monitor won't enter power save mode

involved using xset dpms force standby. I also tried xset dpms force off. Both results were the same: both monitors would go black, then one would power down and when the other powered down, they would both power back up. With both commands, the screens were visible rather than remaining black.

• Monitor/display power saving no longer working after 20.04.1 LTS update

suggested dpkg-reconfigure gdm3 which had no visible effects on my installation.

Any thoughts or insights would be most appreciated!

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EDIT: The issue still exists after a fresh install of 21.10.

EDIT: The issue still exists after do-release-upgrade to 22.04.