I'm nost sure we are all on the same page. Whoever is advocating for no additional heat-sync, I'm with you. This NVMe has a heat-sync. It's not the largest or most aggressive looking heat-sync but it is there from the manufacturer. I'd just go with that and leave it be. If not, then I'd say to remove that one and install the one on the MB. If you really want to go all out, you'd still need to remove the heat-sync that came with the drive and then you could install any heat-sync that you like. For me, I'd consider my options in the following order:
1) Use the current heat-sync only
2) Remove the current heat-sync and use the one on the MB
3) Remove the current one and use a 3rd party heat-sync