Samsung QVO 970 SSD not recognized // recover SSD data

Hello,

I've been using the Banana Pi M2 Ultra for 2 years now as a mini 24/7 server with NAS and wireguard functionality etc.

I started with a Crucial MX500 1TB SSD connected with the SATA interface and formatted as ext4, but not as OS partition, just for data.

A few months ago the ssd occasionally disappeared and I had to  restart / poweroff the device and after a restart everything was OK.

But not the last time - after mounting the ssd I was shown an blank, empty ssd with no files.

Testdisk shows all folders from the "root" folder of the partition, but nothing else, extundelete could also no help.

So first question is: How can I best try to recover files / data?

Crucial support was no help at all. No software or anything - only hint was to run fsck.

OK, luckily there are no really "crucial" data on the disc. So I ordered a Samsung SSD QVO 970 2TB.

But this one - while working properly with my Windows PCs - is not recognized at all - neither with the SATA interface

nor with a USB -> SATA adapter. Both ways work with the old SSD without problems.

So second question: What can I do / what has to be changed??

Regards,

Mario