Basic Homestay booking record app

I need an offline basic app for booking homestay reservations on a multi year calendar [login to view URL] is the closest to my requirements I don't have a hosting server. Developer needs to make my firebase free hosting server if needed for server configurations. I don't intend to purchase any hosting service for this app. No hidden costs involved I just need an app for my personal use on phone.. Very simple and easy If developer can make this without server and completely native , I have no problems. I don't have any expertise in this. I have a backend file created earlier as attached