USB C enclosure for SSD not getting reliable speed when using USB 3

I did test with 2 enclosures on 2 different computers and I’m getting the same result on OSX but on Windows it’s fine. The M2 drive speed looks ok when connected directly to the motherboard with the M2 connector.

The read speed is not reliable and sometime is around 90MB/s when the enclosure is connected to a computer running 10.14.6. (see attachment)

When I use the same enclosure on the same machine but booted on Windows 10, the speed looks reliable. Is these something we can do?

Two enclosures tested :

https://www.amazon.ca/-/fr/gp/product/B0...

https://www.amazon.ca/-/fr/gp/product/B0...

The SSD drive :

https://www.amazon.ca/-/fr/gp/product/B0...

The laptop computer: MacbookPro Retina 15”, mid-2015, 10.14.6

The desktop computer: Gigabyte Z370 Ultra Gaming, 10.14.6 and Windows 10.

I did a test with the SSD drive plugged into M2 connector on OSX and it's giving me unliable speed as well. It’s usually around 2000-3000 MB/s, but now, after a stress on the drive it shows between 160-500 Mb/s.