Yes, you can 3d print dry boxes for your MMU2s spool holders.
They consist of two parts: the frame and the cover.
Use PLA or PET-G, 0.3 mm DRAFT MK3 profile of Prusa Slicer.
For the base use only bridging instead of supports, set 45 degree bridging angle as shown on the picture.
The cover is to be printed in vase mode. Do not worry about the curved walls - it does not affect final functionality (and even looks "organic"). It is not necessary to use transparent filament for the cover because you probably could not see the spool`s spinning thru it.
It would be better to fix the frames on the spool holders with any glue or silicone.
Every frame has three holes for a filament which you can use with or without PTFE tubes.