Since I last posted on this topic, I've found that the random reboots only occur when there are Windows Server VMs on the host (Tested with 2019 and 2022). The issue will not occur when running Linux VMs.
My issue seems very similar to the problem described (and solved) in https://xcp-ng.org/forum/topic/6683/windows-server-2019-sporadic-reboot/7
The difference is that in my case, the host restarted and in the other post, the poster reports that the VMs are restarting. Since the poster also tested RAM and found no problems but was able to solve the issue by replacing a suspected DIMM, that information may be useful in the host reboot scenario that I experience.
FYI, I have not replaced the RAM yet and may not actually do it since the server in question is aging and will likely be replaced (with HP hardware) soon.