@elixirtrip well some info is already here. For now there is a board that can go to can bus without a driver and you can attach your own external closed loop (leadshine, odrive ..):

https://forum.duet3d.com/topic/16257/ac-servo-motor-driver-control-by-duet-3-mb6hc-help/5

https://forum.duet3d.com/topic/17148/duet-3-expansion-1xd-can-fd-single-external-driver-controller?_=1592917797395

https://forum.duet3d.com/topic/15975/duet-3-nema-23-closed-loop-with-z-axis-also-using-elec-brake/16