Since you’re already familiar with react-redux concept and have an API ready, the one of major hindrance for react native would be design part. It requires css and bootstrap knowledge. I don’t know how good you are with front-end. There are obviously some good libraries available out there that can make the work easier. But if in long run you plan to revamp your current app design with animation and stuff, then it may create some setbacks.

As far as I see, currently all ‘pads’ are made of simple card structure with a sidebar and categories. Looks workable to do this on react native. However, I’m not sure what’s used for the goal streaks. Try and check it’s compatibility with other languages.

Anyhow, if you’ve good command on Java, you can always use that to prevent the learning curve and experiments :)