Build me an cross-platform application

I want a cross-platform application. It is a simple application. This application’s main aim is to store data of various PGs and take payment from the customers when they book any bed for a stay in PG(Paying Guest).

It consists of two parts –
1. one app is for customer where they can book beds in PG
2. second app is for the partners where they can register their PG property

Tech stack required –
1- Flutter
2- Dart
3- Firebase
4- AWS Lambda

Little changes in the tech stack can be made according to the related skill set of the developer. You can make a bid if you are capable of making a cross-platform application with flutter