[{"_id":"1","isDeleted":false,"user":{"name":"john2","phone":"+012345678912","highPrivacy":false}},{"_id":"2","isDeleted":false,"user":{"name":"john2","phone":"+012345678912","highPrivacy":true}}]

db.collection.aggregate([{"$match":{"isDeleted":false}},{"$project":{"isDeleted":1,"user.name":1,"user.highPrivacy":1,"user.phone":{"$cond":{if:{$eq:["$user.highPrivacy",true],},then:"$user.phone",else:"$$REMOVE"}},}},])