Optimize Flutter Story-Sharing App

I need a Flutter-based story-sharing app improvements (similar to Instagram Reels/WhatsApp Status) with the following features:

The app is already working the users can upload sotires, the users can view sotries, scroll through them, play/pause and has the right and left touch feature also, so you need to only implement pagination in it, the app is using firebase cloud and storage. I already have the app made using the story_view package with liking feature but it feels slow

REQUIRE - PAGINATION / LAZY LOADING / PRE LOADING and SWITCH BETWEEN 'LATEST" and "MOST LIKED".

Ultra-Fast Pagination & Loading
Critical: Implement efficient Firestore pagination (load first batch on app start, then lazy-load more).
Optimized Firebase Storage for fast media retrieval.
Pre-load next stories without lag.

3) UI/UX Enhancements
Top toggle arrow to switch between "Latest" and "Popular" stories (sorted by likes/views).
Smooth transitions between stories.

5) What I Provide:
Story upload screen.
Current story_view implementation (to be improved).

Deadline: 2 days max