The cheap Samsung enterprise m.2 drives you see on eBay have been trouble for me and others. The things have a tendency to suddenly fail with the firmware version displaying as “ERRORMOD” (error mode) and only showing 1GB of unusable space. They can potentially be put back into a usable state, but it’s 100% data loss when you see that message.

Samsung’s consumer and enterprise SSD departments were (unsure if still true) basically separate entities that didn’t talk with each other, which was further confused and compounded by the OEM customized firmware nonsense which results in a lot of great hardware essentially having buggy firmware with no fixes.

I believe their very latest (non OEM) enterprise m.2 drives have streamlined the availability of updating the firmware, so the problem is seemingly less for those.

For the silicon power drives, if they just suddenly stopped showing up, then you may try doing a power cycle to see if that brings them back: https://dfarq.homeip.net/fix-dead-ssd/

I’ve had Intel and consumer Samsung drives I’ve brought back with power cycling. Older NVMe Drives seem especially prone to becoming unresponsive in older NVMe enclosures. Seems like less of an issue these days though.