Some of my VMs in ESXi were unreachable after a while – maybe this was the issue… Maybe this is the fix…

Tecmint – Disable Suspend and Hibernation in Linux

This issue seems a little more pervasive on Ubuntu 24.04 Desktop – even with sleep and hibernation turned off.

So now – I’ve set the screen to never go black – and we’ll see if that works.
It is certainly not an “ideal fix” – or a fix at all – but seems better than having to constantly power-cycle the VM.