Advice Needed: Best Approach for Building One Codebase App for iOS and Android?

Hey everyone,

I’ve mostly worked with .NET and web apps until now, but I’ve recently been asked to help build a mobile app for both iOS and Android. The goal is to maintain a single codebase as much as possible, since the app is fairly straightforward — user auth, data sync, basic CRUD features, push notifications, and offline support.

We’re debating between going with Flutter, React Native, or doing native development split between Swift and Kotlin (which feels like double the work).

Has anyone here worked on a similar kind of project?

How was your experience with cross-platform tools like Flutter or RN in terms of performance, native look & feel, and maintenance?

Are there any major roadblocks I should know about when dealing with push notifications or background tasks on either platform?

Appreciate any insights or suggestions.

Thanks in advance!

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