So I tried (in SSH):

reboot

Which wanted to work, but shutting down services was still not going anywhere after 15 minutes.

After some searching (yes, you can hold the power button 2 seconds for a controlled shutdown, or 5 seconds for a hard shutdown), I found this and it work great in these kind of emergencies:

kill 1

I did find it challenging to find a good explanation, but as far as I recall, PID "1" is the kernel, and if that process dies all other processes get killed automatically.

I see other recommend the following kill command but I have not tested this on my QNAP as it was already rebooting. It basically kills all processes except the process that is running the kill command.

kill -9 -1

I hope this useful to someone ... 😊