The app itself would be pretty easy, with a login for pre-registered users and a simple interface where to select some data from dropdowns and geolocation, that will give results based on a number of information in the Excell sheets.
Those results, however, are given through advanced macros inside the Excell, which is the point of my concern about actually building this app.
There is a way to import the Excell with all the macros and make the app working as the Excell file?
You’d have to have to convert the Excel file to a Google Sheet, and then reimplement the Excel macro functions using Google Apps Script. Depending on how complex the macros are, this could be either a trivial or non-trivial exercise.
I’ve just been through this process myself, and it wasn’t too painful