PCIE 4.0 NVMe SSD Roundup
If you put the drives in heatsink size order like the famous Tower of Hanoi game then it would look like this graph. Bigger heatsinks lead to lower temperatures. Not exactly a result which will hit the front pages, even if the "no heatspreader at all" Seagate FireCuda 520 is well inside thermal limits.
Taking off the heatsinks and leaving the temperature management solely to the motherboard heatspreader/heatsink brings a whole different set of results. What is perhaps most surprising is how effective a motherboard heatspreader is. Given that all these drives are double sided then perhaps the big surface area of the motherboard cooling is doing a better job than the supplied heatsinks which, let's not kid ourselves, have some aesthetic considerations.