It’s often said that a brilliant football player does not a good manager make, and the reverse is also true.
Sir Alex Ferguson for example, was a player that wasn’t anything special but remains the greatest manager of the modern era.
Pep Guardiola is going some way to disproving the saying and Zinedine Zidane deserves a mention too, albeit his managerial career hasn’t really had any longevity at this point.
Xavi Hernandez was the finest of midfielders for Barcelona, but he’s certainly been found wanting as coach of the club.
One has to take his circumstances into account of course.