So with most M.2 enclosures the speed is slowed down to the level of the USB interface (1000 MB/s) unless you have an enclosure and an interface with USB3.2 Gen2 2x2 20Gbps then it is slowed down to 2000 MB/s.
3000 MB/s, which the M.2 SSD achieves internally, is not reached.
Nevertheless, these are already decent values that put every USB stick in the shade.

I think it will be slower, you have a direct interface on the mainboard. The question is whether you need it and can use it.