App using Geo location to manage client visits automatically

I am looking for a developer that is confident that they can create an app that essentially compares a worker's current location to that of their registered clients to log when they were on site and to help use this information to create invoices, manage simple communication with the client and log new jobs. The two main components are geo-location to to determine workers current location and a scheduler to define the times that they are expected to work, and the client that they are supposed to be visiting. The App needs to be able to cope with multiple clients with multiple employees, each with their own schedule. An admin will set up the schedules in advance using access via a website, but will also be able to review what was scheduled and what was actually worked. Data should not be accessibe between different client organisations, and there will be access hierarchies within the individual organisations. It is expected that the selected developer will help to get the App published to both the Android Play and Apple App Store.

Key items
1 - App
2 - Website
3 - Integration with Quickbooks
4 - Publish to Android and Apple stores

Attached is the working requirements document along with a previous attempt by a developer that gives an idea of what is required

It has been suggested that I use Flutter and Firebase to develop the app but I am open to suggestions.