Looking for a WordPress solution to enter data and to create different graphs for different customers

Hi There,

A customer of mine uses an excelsheet at the moment to enter data for its customers. Customers are girls and boys who come to their shop for nutrion plans, workout plans, consult and supplies (like protein).

My customer is looking for an integrated WordPress website solution. In the most basic form it is an excelsheet with formulas that can calculate body mass index, weight and fat loss progression, etc. for each customer and stores the data on a harddrive. Solution should be accessible from different Mac computers.

In its most complexform it is this plugin: https://codecanyon.net/item/-wpgym-wordpress-gym-management-system/13352964 -> My customer already indicated that this solution is to heavy/large for them.

I have tried to use google to find a fitting solution but did not succeed. Does anyone here maybe have tips, ideas, plugins to look at, etc?

Thank yo very much for your answer.