mmsoar received kudos from Peter Randziak in eamonm.sys BSOD - Stop code: SYSTEM_THREAD_EXCEPTION NOT HANDLED
Updated last night to KB5004237.
So far the system appears stable. At least the MTBF is > 12 hours.
So, whatever the changes are they appear to have largely resolved the rapid bug check issues.
If the problems re-occurs I'll re-post, but for now, thankfully, I'll retire into the background.