I used these for my two Samsung 970 EVO PLus NVMe drives for a while, when I used a different motherboard.
They were pretty good
EK M2 NVMe Heatsink (comes in different colors)
EDIT: I wouldn't feel comfortable using the drives without heatsinks, they do run hot after a while - and I would like to extend the lifespan, but also stay below the drive throttle temperature limit, to acheive maximum performance for longer (actually I never hit the throttle limit with the heatsinks). If the drive begins throttling, there not really any point in buying high speed storage, at least that's what I beleive.
But remember, the integrated heatsinks on some motherboards do n othing good for cooling, and I've seen tests with increased max temparature. That's why I used the custom heatsinks with my previous motherbord, but the integrated heatsinks on my current board are fairly good, so that's what I use now.