It's different between coaches and players, so coaches have nothing to do with a person's career as a football player and there are even some great coaches who are not basically football players.
The majority of great coaches are footballers. e.g. Guardiola, Dieogo Simione, Zinedine Zidane, Carlo Anceloti, Jurgen Klop and more.
While those who are not from former players are very few but can be successful because of learning and from assistant coaches, even jose mourinho only started as a translator for a coach.
yes one example of a coach who is not from a former player and a great success yes jose mourinho