Multiple Apps in Play Store, some free, some Paid, one Backend

Hello, I have an online running Vaadin Project that spits info, I would like to develop multiple mobile apps for different user groups, different logos, themes, even services, to serve them.

I thought of PWA, with Vaadin but i ran into issues last year as it seems I need to learn about domain names to server these different apps, now I thought of using React Native, while developing with VS Code, Hilla came to my attention,

2 questions:
The thing is seems like I need to have a copy of the backend Vaadin Project to start working on the different Hilla App Projects I would like to develop? or is there another way? Should I copy the backend project for each Hilla App i am developing or customizing?

Will I be able to use In App Purchases like the google store or iOS play store API to make purchases?

Thank you