Cool stuff,
I tried it out and it worked right away; I’ve tried a dragon here
I recently did something similar (a model viewer) - which you can find here 3d model viewer for Monogame [ver 0.6]
I think for your model viewer it would be helpful if one could rotate the model in other directions, too. Plus I think it would help a lot if one could use mouse inputs, too.
Apart from that, obviously stuff like sliders etc. are nice to have, and if you don’t want to do them yourself there are a number of GUIs that are updated frequently, for example:
myra Myra - UI Library for the MonoGame
geonbit.ui GeonBit.UI: UI extension for MonoGame