Yeah, I would also get raw but with the 720 battery. I’d want to use my current wheelset, but it’s got a XD. I suppose I could swap it for an HG hub driver though.Same approach here - frame only, with the 960W battery, raw finish. I expect it to be silly expensive, though.
Rear hub is a standard 148x12mm setup, no proprietary sizes there. It is the Shimano HG type with which the Gates rear belt sprocket is compatible. Onyx Classic 148x12mm Singlespeed Boost would be my choice (well, in the dream-land).
More tech info here: 2024 SATURN 16 MGU Tech Sheet