UPDATE: The QNAP problem I described in the post above came back last weekend. QNAP published a new version of firmware. I downloaded it and installed it on Sunday morning. When the system rebooted the spontaneous reboots returned. I was still convinced it was the Roon Server App on the QNAP so I stopped the service and uninstalled it and reinstalled it. At that point I noticed that doing almost any task would cause my QNAP to reboot. It was at that point that I decided it was the memory.
When I bought my QNAP I upgraded the memory from the 4GB that it came with to 16GB the max it will accommodate. I purchased a 16GB memory kit from Crucial Tech and have been running it for 2 plus years with no issues. I opened the unit and reinstalled the original 4GB that came with the machine. This stabilized the unit and all my reboot issues disappeared. My QNAP is now rock solid stable again. It was the memory. I have never had any memory go bad before so it was the last place I thought to look.
Since going back to 4GB I have noticed that at times Roon seems a bit slower. It takes a bit longer to bring screens up and it just feels slower. According to the Resource Monitor my 4GB memory is being 42% utilized. I decided to buy another 16GB memory kit. Crucial has a lifetime warranty on the memory however I cannot remember where I bought it and so I can’t find the receipt which is needed for a warranty claim. The new memory is coming today however I probably won’t install it until later in the week as I want to run the system for a bit with the 4GB installed to see if I get any random reboots.
This was a lesson learned for me. I spent a lot of time testing and trying stuff out only to have the system reboot again and again until I hit upon it. Hopefully do one else experiences this issue but in the off chance that you do, check that memory. By the way, the tech at QNAP that I spoke with suggested this as a solution early on but to be fair he also suggested that it could be the UPS that the unit was plugged into as well so I ignored his suggestion. He was right about the memory at least.
I am now considering this a closed issue and calling it fixed.