Decide Platform Strategy

Background: I'm deciding how to build [app description]. My situation:
- Team / skills: [your iOS, Android, and shared experience]
- Timeline and budget: [constraints]
- Audience: [where your users are—iOS-heavy, Android-heavy, global]
- Key features: [anything platform-sensitive: widgets, background, AR,
  Bluetooth, deep OS integration]

Use case: Help me decide between native iOS only, native Android only,
both natively, or a cross-platform approach—and commit to a defensible
choice.

Implementation details: I'm leaning toward native (SwiftUI/Combine and/or
Jetpack Compose). Pressure-test that against cross-platform (e.g., KMP,
Flutter, React Native) given my constraints. Be honest about the
maintenance cost of two native codebases.

Deliverable: A recommendation with reasoning, a comparison table of the
options against my constraints, the main risk of the recommended path,
and what would have to be true for me to choose differently.