Hi, I bought the Samsung 990 Pro instead of the Kingston NV3 because the first one didn't work. Samsung works. But I did not use an additional heatsink. I use it for Time Machine backups. So unfortunately can't help. Sorry.

I have the same SSD and it also gets relatively warm. But as there is no space, there is an adhesive pad for cooling in the hub. Have you at least stuck it to the SSD? If you have found a better solution, I would also be interested.

Personally, I've installed a WD Black SN850X card and I've had no problems with overheating and the Mac is powered on all day.

Hi, I quickly found this article here:
https://www.reddit.com/r...
However, it doesn't say how the thing stands, without the lid. Because there are rubber studs on the lid. I could imagine that the lid could be cut out accordingly. Then the whole thing stands neatly on the table again. This solution is probably only suitable if you are willing to "tinker".
Good luck ;)