[{"gameId":"string","markets":{"market X":{"instagram":"string","lastVersion":0,"market":"market X","name":"string","supportedVersion":0,"telegram":"string","config":{"A":1,"B":2,"C":"c"}},"market Z":{"instagram":"string","lastVersion":0,"market":"market Z","name":"string","supportedVersion":0,"telegram":"string","config":{"D":5,"E":8,"F":"vb"}}}}]

db.collection.aggregate([{"$addFields":{"x":{"$map":{"input":{"$objectToArray":"$markets"},"in":"$$this.v"}}}},{"$unset":"x.config"},{"$addFields":{"x.gameId":"$gameId"}},{"$unwind":"$x"},{"$replaceWith":"$x"}])