Well, a little bit of history to begin with.
Sys specs:
Proc: i7 9700k
MB: Gigabyte Z390 Aorus Pro
Ram: 8GBx4 DDR3 Corsair Dominator 3200Mhz
Storage: Samsung 970 Evo Plus 500 GB, Seagate 1TB HDD
Gfx: Nvidia 3080
OS: Win 11 with latest update installed
BIOS is running in UEFI mode
So, had bought this spanking new SSD from WD, knowing well that I would have to live with reduced speed as I’ll be using it on a Gen3 pipeline (thought to keep my purchase future proof). Wanted to mostly use the WD SSD for game storage as I’ve everything else including the OS on the 970 Evo.
My MB has two M2 slots, and the Samsung works flawlessly in both. When I inserted the WD SSD into the empty slot, it outright stopped the sys from booting into the BIOS. Even changing the slots didn’t help. Then a light bulb moment 
Burned a Win11 bootable disc, set boot sequence for the removable Disc drive, removed the 970 completely, inserted the 850, booted from the Disc drive, formatted the 850, then re-inserted the 970 and voila, 850 showed up like a charm.
I have absolutely freaking no idea why WD would put me through such a hassle to get their drive working. 970 never had such an issue.
Then WD Dashboard app. gave an error that the drive health of the 850 was critical and needed replacement (huh! wasn’t it a new product? guess these things happen). Had to go through the, not so hassle free, RMA process and got another new replacement 850.
Inserted the new 850 after removing the 970, connected the Disc drive, but the Disc drive failed to light up (tried a lot but nothing happened), so, couldn’t boot from the bootable disc. Removed the 850, connected back the 970, sys came alive. Connected the Disc drive, it worked normally (what!!!). At this point I’ve no idea what the hell is going on.
I’ve had a brush with WD tech support for the earlier 850 and it was abysmal, so, thought to rake the more knowledgeable minds of the community to unravel the mystery.
If you have read this far, thanks for your patience 
… And if you can help out, then you are amazing 
