Choosing a Navigation Pattern for a Cross-Platform Fintech App

You're the lead designer for a new fintech app launching on both iOS and Android simultaneously. The product team is split: one group wants strict adherence to each platform's native navigation pattern (bottom tab bar + in-app back button on iOS, navigation drawer or bottom nav + system back gesture on Android); another group wants an identical navigation shell and icon set on both platforms so support documentation, screenshots, and user habits transfer directly between devices.

1. Lay out the real tradeoff each side is making — not just "which one is right" but what each side is actually trading away.
2. For a fintech app specifically (where trust, security perception, and low error tolerance matter a lot), which factors would push you toward one side over the other?
3. Propose a middle-ground approach, if one exists, and name specifically what would and wouldn't be shared across platforms.