How to take the NAS (or a Pool) offline

For security reasons I want to take the NAS offline when not in use, for example by keeping it turned on only for backups.
Initially I thought of taking only one pool offline so I could use the others 24/7, but with “zpool export/import” I only created problems.
The only other alternative I can think of is to turn on the NAS only when we need it and turn it off when the job is done using scripts.
However, this means that two NAS must be created, a work one that is always turned on and one that is turned on only when needed.

How would you solve the problem?

Will these times of need follow a schedule?

What is your hardware? You could start the NAS via IPMI (or similar).

I don’t think the motherboard supports IPMI.
Instead, I already know that I can turn on the NAS at a certain time by configuring the MB, but obviously I couldn’t change this time remotely.
Or I could turn it on via WOL through another device either with scripts or by hand when I need it.

What I would like to do is start specific backups from other devices.
If it were possible to start a pool (and then take it down when the job was done), then I could also make backups from the other pools.