Create a mapping table between 3 tables which have Many-to-Many relationships among all tables?

Hello all,

I want to calculate the Impact Amount for each client that is based on activities that the client does. Followed by flow and impact. I have 3 tables that do not have unique columns that can be used to create relationships for Tables A to C. Every column has redundant values that are causing to have Many-to-Many relationship in PowerBI. These Tables follow a hierarchy in order to calculate the Impact amount for each Client. Data hierarchy of the tables
These are my tables.

Your help is appreciated thanks!