I love the way the markdown editor works in that app, and believe it's something that The Joplin mobile apps should do as well. Perhaps a colaboration with that app's author would be beneficial to both apps.
I probably have mentioned in the 25 threads about a better editor on mobile. But here it goes again. We use react-native. We cannot use native editors. So unless you give us a react-native editor that works, all discussion is useless.