I really think you’re wrong there.
Wrong about what? Agents don't know everyone's wages, each players contracts are different and part of a private negotiation, the only persons that know a certain player wage is the player himself, his agent and the club. It's not as easy or straightforward to have a player wage and players tend to not share the information with their teammates. As far as I know CAA doesn't have United players as clients, so there is no immediate reason for a player/agent to have the exact terms of Varane's contract.
And Varane thinking about leaving is a fact that his agent has openly talked about since 2018.