Is the windows clean install or not? Like did you done a clean install on the nvme only? So bios settings necesarry has been set as per what you said, windows installer on gpt (if you use rufus, before burning the iso set it to gpt), then install it on the m2 ssd after the ssd been converted to gpt? TL;DR: SSD formatted to gpt + windows installer on gpt? And you do sure your nvme is not faulty and/or the adapter not faulty? NVMe drives usually appears on Storage Controllers instead of IDE ATA/ATAPI Controllers list.
AFAIK Yes i did plug the nvme + the adapter, preformatted it to gpt before using it on that z68 of mine (was)
If you do need the driver (well it might not affects it at all since this is sata drivers), try this . Chipset driver use this, and ME driver use this.
Im pretty sure you do know how to install .inf drivers through Device Manager.
And please re check, if you did everything and every setting in the bios, after you save andexit enter the bios again and check wether the settings you’ve changed reverted/unchanged or changed, if it’s changed as per what you did set, then it should be ok, just do another save and exit.
If you do plan to clean install everything, make sure to re download the windows of your choice .iso, use the latest rufus and set the installation to UEFI + GPT (no CSM), burn it to your flash drive, when you boot to the windows install bootable you just made with rufus, Shift + F10, diskpart, list disk and sel disk x (x = your nvme in the list disk lists), clean all (this will nuke the entire ssd, usually clean is enough instead of clean all), wait a bit till it finishes, then convert gpt, wait till it finishes, and after it finishes proceed to install windows using custom option → choose the uninitialized nvme (not even formatted to ntfs, just gpt configured), install but dont forget to disconnect the internet, then go to windows, install the Chipset Driver → restart later, and ME Drivers (AHCI Drivers are optional) i gave, reboot, and you’re good to go to install any drivers, the point is after installing windows do not connect to internet untill chipset driver and ME drivers are installed and did a good reboot, so that windows update wont mess with your installation.