MonoGame for gamified, "serious" apps?

Hi everybody,

I’m coming from a Unity game-development background, and my next task and ambition will be to create a truly cross-platform app (Win, Mac, iOS, Android, if everything goes well) with a more visual, gamified look and feel compared to usual apps.
Since Unity would be a bit heavy for that task, I came to Xamarin, but soon learned that Xamarin requires you to (re-)write your GUI for every platform individually (if you don’t use the rather limited Xamarin.Forms).

My question to you is: Would it be a viable and recommendable option to use MonoGame in conjunction with Xamarin to create a rather graphics-intense “serious” cross-platform app with a unified look on all platforms?
Would it perhaps even be possible to combine graphics rendered by MonoGame with some native UI-elements coming from Xamarins libraries? (not absolutely necessary…)

Or would ‘MonoGame for apps’ be a rather bad idea?