There are some bugs with Windows MR in Orbus. Specifically, haptic feedback doesn’t work. This is primarily a problem with fishing, but the devs added a visual cue to work around this:
There were problems with the tutorial, however that part of the game has been revamped since this post, so it may no longer be relevant:
The developers have said they want to support WMR in the future:
Without having a WMR, I can’t say for sure, but it sounds like WMR works decently with Orbus as long as you can tolerate some minor bugs.