I'm a C#.NET Core developer. As mobile app development sells more, I hope to upgrade my career to a mobile app developer. I'm looking at Xamarin Forms or Java. What would you advise?
It depends. Xamarin is a good jump start for cross dev.
But there are other tools that might get you down the road with a simple but catchy portfolio to get some attention from the market. PhoneGap is one of them.
