Android MVP Event Booking App ! Do not apply INDIAN DEVELOPERS

I need an Android-only MVP that lets customers discover our events, reserve a spot, pay, and then see the confirmed booking appear in their Google Calendar automatically. The flow is straightforward: event list → detail screen → seat/quantity selection → checkout → confirmation. Payment must accept credit or debit cards, popular digital wallets, and direct bank transfers from day one. If you already work with gateways that bundle these (for example Stripe or Razorpay alternatives), let me know which SDK you prefer and why; I’m open as long as all three methods are available to the user inside the app with a single, clean checkout experience. Calendar sync is limited to Google Calendar for this phase. Once a booking is successful the event details, date, time, and location should be pushed instantly to the user’s Google Calendar with a reminder set 24 hours before the event. Guests should also be able to remove or update their reservation and have the calendar entry reflect that change. Because this is an MVP, visual polish can be minimal; stability, simple navigation, and well-structured code matter more. I will want the full Android Studio project, a signed APK suitable for internal testing, and a short read-me that explains the build steps, third-party services used, and where to swap keys or credentials. Please note: I am only considering developers located outside India for this project.