Assuming 970 Samsung Evo
Safe Operating Temperature
0 - 70 ℃ Operating Temperature
EK make M2 block, check it won't foul on components around the M2 drive before purchase.
You remove the *sticker covering the m2 drive chips (on the top only normally) and place the EK m2 cover on, should have thermal contact pad as the interface material between chipset and heatsink.
There are cheaper versions on eBay and ones with fans or RGB around from different manufacturers. If your motherboard comes with one use that.
* I live in Australia, and we have strong consumer laws, the void if removed, warranty crap on stickers don't hold up here as reasonable excuse to void warranty YMMV. If in doubt take photos of the sticker before removal and after and then the M2 with heatsink interface on with dates stamps. And you have future warranty unless the manufacturer is terrible. I have found Samsung are quite good for warranty.
Hope you find this of help.
that's funny, I have the exact same issue with the same mobo and a Samsung 970 Evo Plus. around 62°C or so, I get a random shutdown.
I replaced the thermal pads and put a 60mm Noctua fan in front of it, so far it hasn't exceeded 59°C, no more random shutdowns, but it's definitely not normal.
Any update on your side?