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.
It's a bias.
There are some great coaches who weren't football players,
but most of good coaches were football players.
It's make sense because you can't feel a sense how a good strategy and team play was supposed to, the way is become the player. Arsene Wenger is one of most popular coaches who wasn't a player.
As far as I know Wenger played as a professional player at Strasbourg, one of the clubs in Ligue 1 but there is no achievement to be proud of there.
But that does not mean there are no coaches who have not been players before because there are several coaches such as Maurizio Sarri, Brandon Rodgers and even Julian Nagelsmann. They never once registered as professional players but their achievements as coaches can be said to be very good.
Actually starting from a professional player or never having been a professional player at all has nothing to do with achievements in coaching but at least until now when looking at some of the current coaches it is more from professional players first because it is indeed a stumbling block for them because they have felt before when they were players but now they apply in something different as a tactic processor but their experience in the field as a player is used as a complement for them to be able to know what to do when as a coach.