TIL - you are supposed to remove the "Laird" sticker cover off the M.2 drive's Heatsink of your Motherboard
I built my own PC (or rather technically stripped out the Factory build from the Case - and replaced with entirely all new parts) - and wondered why every so often my M.2 NVMe drive would stop working as if it was dead - and then resurrect when I removed and re-seated it
TIL the sticker on the back of the M.2 Heatsink of my Asus Z390-F Motherboard says "Remove" - after 6 years