Turned off after power return

StephenB, I really appreciate your willingness to help and the fact that you provide a detailed solution. Thanks for this!
I use the NAS in a different mode, namely from time to time. I have several of them, but I use some of them every few days or even weeks. I just have a backup there and synchronize data from time to time.
If I turn on the NAS, then at 2:00 at night it automatically turns off (I waited for a long time for OS6 to have a function that only turns off the NAS. At first in OS6 there was only one that turned on and off, and that did not suit me).
I often go away and then turn off the power supply to the circuits at home. After returning, I turn on and all NAS'es turn on, regardless of what I did. There is just a supply voltage and they all turn on.
I want to move one or two NAS'es to other locations. They will be enabled only during backup. I do not want them to be exposed to voltage outages. Why? Because voltage flapping may occur. Even in this forum cases of damage to devices are described, when the voltage appears and disappears.
I expect one simple thing (and not only me): that it will simply not turn on itself (I'm always able to turn it on via WOL). I really like Netgear, but the lack of such functionality makes me think about changing the device to another brand, at least those that don't have UPS.