Not with that exact number, but on my last job change my demand was equally precise. Although we reached an agreement, my new boss said that this was "an oddly specific number" and she'd never experienced that before.
http://hjerpbakk.com I try to write an article every time Google search fails to help me solve a problem. I also write about my personal projects and what I've learned as a leader and software engineer.
Mono is still used on mobile, but a unification will occur in the future when .Net Framework is sunset and all there is is .Net 5. .Net will target Windows, Linux, macOS, iOS, Android, tvOS, watchOS and WebAssembly ++
I've used Xamarin Forms privately since beta when it was just a little experiment, through now when it's an integral part of Microsoft's strategy. I've also used it professionally, with good results.
The difference from 3 years ago is night and day.
The kinks are worked out, the framework is performant, the devex glorious and you can freely mix Forms and native creating any mobile experience. The libraries are stable and XAML together with simple patterns makes you really productive, really fast. A perfect match for dotnet-heavy shops, great for everyone else too, but maybe not the right match if you live and breathe JS.
[ my public key: https://keybase.io/hjerpbakk; my proof: https://keybase.io/hjerpbakk/sigs/ent0T4UG2yyrIhr4S2hzahX9YpiCh7t4JFge1JtFUOc ]