I'm a noob who have struggling with this for hours. Tried a lot of stuff (including trying to use AppCompact and ContactsPlugin (maybe those would work, but I just wasn't able to achieve it)) and nothing.
If you have a simple solution, it would be ideal.
Well, the answer turned out to be disappointing: at this moment, there's no simple way and it's better to just work natively on each version (in any case, there seems to be a way to add native code to your Xamarin project, but it's useless if you already write the most important things separately)