Database
[{"_id":"61f9b4b59f6601076fff7682","league":"61f1db496de13b0505f08c83","rank":1,"team":{_id:"61f86e813bce5a7bfce4eb6a",name:"ZizoTeam"},"createdAt":"2022-02-01T22:31:17.808Z","updatedAt":"2022-02-01T22:31:17.808Z","__v":0}]
Query
db.collection.aggregate([{$addFields:{name:"$team.name"}},{$project:{team:0}}])