Leaving the previous post up as a warning for future me's.

Don't follow it. Do not use the X725.

As it turns out, it can (and will) at some point fry the SD card, leaving you with a bricked NAS. From the looks of it, chances of this are highest when it loses main power, which you'd think would be the main point of a battery-backed UPS system.

It is not a question of whether this will happen, but when. For me it was a few months. Luckily, this was only the SD card; the RAID array and the Pi itself were fine.

Anyway, since being able to have remote and timed startups and shutdowns, I have no converted the system to one with an official PoE-Hat, and a PoE switch that can be controlled remotely. It wakes up every night for backup tasks, and then nicely goes to sleep again.

So far, amazingly, without destroying the SD card :)