Unitek External CD DVD Drive, USB3.0/USB C Portable CD/DVD Player ...
USB/TYPE 5-in-1 multi-function external mobile optical drive for CD/DVD burner sd card and USB flash disk player dvd drive.
Alert: the M.2 M Key Is Different from the M.2 (B+M) Key!
I doubt that an M.2 drive in an adapter card could perform better when plugged into an X16 slot. I have no deep knowledge of the architecture, but I'm using an adapter card with an old (non-NVME) M.2 drive.
How to Install & Format your M.2 NVMe SSD | Seagate US
How to install and format a M.2 NVMe solid state drive in your gaming PC. ... Insert the drive into the M.2 PCIe slot.