Hey Peter,
indeed the geometry consists of surface-bodies that are not closed - No Solid, no fun! 
Working with 3D-scanned data is a hard task and I checked the data and if i could close the gaps easily for you, so you’ll have a solid Body, but that would require at least some hours of surface-modelling, because of the geometry being already faulty:
Here you see the zebra on the surface and the ZigZag on the edge shows inconsistancies that will make it hard to get to a solid.
I could thicken the surface-bodies by 0,01mm (more wallthickness was not possible) so now you should be able to edit them in Shapr now (in the boundries of the math behind solid-modelling).
Oculus Quest 2 RH manual surface no buttons Refined.shapr (1.3 MB)
Jeah, sure - Shapr would just have to recreate some faces that are not even there, check for the design-intend, solve the inconsistancies,
make some decisions about this and that…
All jokes apart: No CAD-Program in the world can do what you wish for automatically - at least not with a satisfying result.
Shit in = shit out.
HTH
Cheers Matt