Qwiss Edu was to some extent Joorabchian's man. Joorabchian was his agent and has influenced his career trajectory after football. No need to mention Joorabchian is a bit of a piece of shit. Willian and Luiz were Joorabchian players.
Based on my reading, Edu's departure as our sporting director reflects thwarted ambition—there are credible if surprising reports he aimed to be Arsenal CEO—as well as poor sales that meant KSE didn't want Edu to overbid on Šeško last summer, and lastly the Joorabchian-Marinakis connection having opened the door to tripling his income at Forest.
Arteta is a left back pervert but the fans are kidding themselves if they think Edu fell out with him over that.