Nautra: Traditional Accounting App Development

I want to build an Android mobile application based on a traditional village accounting system called "Nautra (Chadava-Utara)".

App Type: Android (Flutter preferred)

Main Features:

1. Login System:
- Mobile OTP login
- User profile (Name, Father Name, Village, Gotra, Mobile)

2. First Screen:
- Two options:
a) I am organizing a Nautra event
b) I am contributing to a Nautra

3. Event System:
- Create event (Shadi, Dhund, Bagda)
- Add event details (name, village, date)

4. Entry System (Core Logic):
- Input: Total amount
- Auto split into:
Utara (old balance)
Chadava (new contribution)

Rules:
- If utara pending, it must be adjusted first
- Chadava is compulsory if utara exists

Example:
Total ₹500 → Utara ₹200 + Chadava ₹300

5. Search & Ledger:
- Search by name, father name, village
- Show full history (chadava/utara)

6. SMS Notification:
- Auto SMS after entry

7. Old Data:
- Manual entry + photo scan (optional later)

8. Reports:
- Total collection
- Pending balances

9. Backend:
- Firebase preferred

10. Admin Panel (basic)

Important:
- App should support long-term data (20+ years)
- Should be simple UI (Hindi)

Please share:
- Your past similar apps
- Estimated cost
- Time required