I contacted Samsung and they told me the EVO 970 is supposed to be used as an internal SSD in a computer. An external USB or thunderbolt enclosure is not supported. Why does Acasis sells then these enclosures?
I replaced the Samsung SSD EVO 970 by a Samsung Pro 980 and the speed of the drive is now better. (read write 2800 MB/sec). The temperature is good (40°C= 104°F) when I put the Acasis enclosure on my Mac Studio. It doesn't run hot anymore.