The outcome of my research is:
- Tried Xamarin's Previewer - am stuck with the designer showing a gray box containing "XFPageRendererView". You can find other users facing the same issue. I tried to follow what they did to overcome it, but without success. Actually none of the solutions presented is really clear. It's worth mentioning a major drawback of this option: you must have a Mac running (at least in the current state of things, this seems to be a bug, not yet fixed) , to which you will connect to as the Mac Agent in Visual Studio, otherwise the previewer does not seem to respond. Like Gorilla Player, requires you to code your UI using XAML.
- Xamarin Forms Player - there is a nuget package, it is a headache to install, because it will (may) conflict with several of your other nuget packages - my workaround here was to manually install all the depencencies/missing ones, one by one, in the Droid project. Still, after being all set and ready to go, I could not go passed the Window with the Connect button. No idea how to proceed from there, what am I supposed to do, how do I finally see the preview. No suceess, followed the docs/the site, to no avail.
- Last and only working option - Gorilla Player. Setup consists of installing a program both in the desktop and in the device. But that's all. Just follow the instructions from the site, and things move smoothly. Drawback: you are forced to code your UI using XAML.