How to recover data from a non-operable NAS disks

[Grover Ellsworth]

My Plextor XStore NAS don’t turn on, it may be out of order.
There is no way to access the files by just connecting the disks to the computer. I can't try replacing the device itself - there is no similar device available.
How to extract data from hard disks after the NAS device broke down, from an inoperable disk array? (I hope that all drives are working and my data is still there)
Is there any well-tested data recovery tools for NAS solutions?

[ed]

This guide should still work https://nascompares.com/recover-raid-or-...p-asustor/

[Grover Ellsworth]

This guide should still work https://nascompares.com/recover-raid-or-...p-asustor/

will this guide work for Plextor XStore NAS?

[Grover Ellsworth]

Thanks for the guide in the previous post.
I recovered my data using Hetman RAID Recovery. 
I recommend.