tldr: I have an existing Android app written in Java. I have solid experience with Java Android but should I re-write my existing app in Java (as I know how), in Kotlin or look at React Native (some experience in React) or Flutter to take advantage of being cross-platform?
I have an App in the Google Play Store (https://play.google.com/store/apps/details?id=com.este.jobcatcher&hl=en). It's had over a thousand downloads with no advertising (bar a post on my personal facebook page) and even a few purchasers. I've not really touched it for the past year or so but I'm now looking at going back to it.
Since I last developed it (roughly a year, maybe less) the mobile development landscape seems to have changed completely. I now have a store of ideas/features/bug fixes that I'd like to implement but I'm almost paralysed when it comes to how to do it.
Basically, I've narrowed it down to 3 options:
Write in in Java for Android because that's what I know and progress will be quick. Then, if it becomes successful/there's enough demand write separate versions for iOS/web. However, it seems like every new Android app is written in Kotlin so if I do re-write/update JobCatcher in Java I'm basically just using an 'old' tech stack(?)
Use React Native. It's similar to React which I've used before, but I didn't particularly like developing with it, and apps made with it don't feel as 'solid' as apps made like 1).
Use Flutter. It's a new framework backed by Google to develop Apps for Android and iOS at the same time. It's still relatively new though and it uses a language I've never touched before and doesn't seem to be used many other places.
I'm open to learning new frameworks but I also have a limited amount of time to get things done outside of my 9-5. Any help would be greatly appreciated! I've been a member of Indiehackers for a while now and always been impressed with the insights people have been able to offer!