I run a Montu M4 and like to give you this hint: With current Raspbian on a Pi4 you need a REAL USB3 cable. The one that is shipped with the M4 will not work!!
Using the USB3 cable connected to one uf the USB3 ports od the Pi4 my Moto M4 got discovered and can be used with Roon Bridge.
The only drawback is, that only two channels are supported by Roon (1+2). Channels 3+4 show a high playback volume but deliver nothing.
My guess is that the M2 will also work with a REAL USB3 cable.