In general, as a coach/admin, you can easily delete a player from the team. You do this via the "Team" menu item. Then click on the "Members" tile.
Then select the player profile of the corresponding player, edit it using the pencil, navigate to the bottom and then select "Delete player".
The player is then removed from the team along with their player profile and all their data.
This is different if the player leaves the team. The player himself will then no longer see the team and will no longer be part of the team from his side.
However, you as the coach/admin will retain the player's data, including the player profile and statistics.
As the player's consent is required, only the player himself can leave the team. As a coach/admin, you cannot simply leave your team, as someone has to manage the team.