I’ve gotten a UGreen NVMe PCIe adapter + Samsung 970 EVO Plus NVMe storage drive for the Mac Pro.
The UGreen NVMe PCIe adapter came with screws, two thermal pads of different thickness and a long heatsink. I’ve noted stacking the two thermal pads weren’t optimal. I’ve noted the Samsung NMVe drive flexed when the two thermal pads were installed. More importantly, there’s still a gap between the thermal pads and heatsink.
So scratch the two thermal pad approach.
I then turned to the single (thicker) thermal pad and noticed it didn’t flex the NVMe drive now, but it wasn’t touching the heatsink fully.
As the NVMe drive runs pretty hot, I’ve applied thermal grease liberally on the surfaces between the heatsink and the thermal pads.