imforumman and others affected by the issue:
The workaround is now included in official LE10 nightly builds (starting with today's 20220610 build)
Add vc4.force_hotplug=3 to /flash/cmdline.txt to activate the workaround on both HDMI ports.
Also please try with 1 and 2 instead of 3 to activate it only on the first or second HDMI port and report back which values work for you.
so long,
Hias