Experienced Developer for Real Estate Platform Performance Optimization (Laravel, Flutter, Next.js)

I am seeking a highly skilled developer or a small team with extensive experience in Laravel, Flutter, and Next.js to significantly optimize the performance of an existing real estate platform. The platform is fully functional and advanced, but a recent codebase review has identified several performance bottlenecks and critical optimization opportunities that need to be addressed to ensure scalability and a superior user experience.

I require clean, robust, and production-safe implementations for all tasks, avoiding temporary fixes.

Key areas of optimization include:

1.  Backend API Optimization (Laravel):
    *  Disable the API curl logger in production environments to eliminate unnecessary overhead.
    *  Optimize the map endpoint to efficiently load only properties visible within the current map area and zoom level. This should include implementing marker clustering for zoomed-out views to improve responsiveness.
    *  Add essential database indexes for frequently accessed filters and search criteria on the following tables and columns:
        *  properties: status, city_id, category_id, user_id, is_featured
        *  users: email
        *  chat_messages: sender_id
        *  notifications: user_id, is_read
        *  Please report any existing indexes that are skipped.
    *  Refactor N+1 queries using eager loading (->with()) across critical sections such as property listings, property details, user chats, favorites, and personalized recommendations.
    *  Implement caching using Cache::remember() with a 3600-second duration for static or infrequently updated data, including system settings, categories, cities, FAQs, and languages. The cache should automatically refresh upon data updates.

2.  Image Handling Optimization:
    *  Backend Image Processing: Implement automatic thumbnail generation upon image upload, creating 'thumb' (200px), 'medium' (600px), and 'large' (1200px) versions, in addition to retaining the 'original'. WebP format is preferred for optimized delivery.
    *  Next.js Frontend Image Optimization: Remove 'unoptimized: true' from image components, configure proper 'remotePatterns' for image sources, and ensure optimized image delivery from the backend domain.

3.  Flutter Mobile App Enhancements (Android & iOS):
    *  Improve the overall loading experience with skeleton/shimmer loading indicators.
    *  Implement lazy loading for home screen sections to reduce initial load times.
    *  Introduce background preloading of non-critical data to enhance perceived performance.
    *  Optimize the splash screen for faster and smoother transitions.

I am looking for proposals that include:
1.  An estimated cost breakdown per task and a total project cost.
2.  A realistic estimated timeline for completion.