The nerve here.
You don't pay 7M€ por reports, mate. You pay them to influence the competitions.
You could say that Barca had a fantastic team but all the national competitions they won are of questionable value. Their smaller in comparison CL success during those years back that.
(During the 17 years Barca paid the ref VP they won 9 leagues and 4 CL. Madrid won more CL, 5 of those, and only 5 leagues)
Going back to the topic, the best I have seen are Modric and Xavi. One is an all-rounder that could thrive in any ecosystem and the other one is more system-specific but reached incredible heights in it. You can not go wrong with either of them. But, certainly, if I had to choose, I wouldn't base it in domestic success, as one team paid the ref VP and the other didn't.