I checked and I do get XNB files produced by the pipeline tool here:
\Randomchaos-MonoGame-Samples-master\Sandboxs\RandomchaosMGPostProcessingSandBox\Content\bin\Windows\Models\bunny.xnb etc.
So I think there is something wrong with my mono game setup and maybe the model loading fails for another reason. Don’t know if it is helpful what I provided here because maybe it isn’t related.