[{"name":"Intrinsic Nubs","is_team":true,"submissions":[{"score":61.77466359705439,"time":{"$date":{"$numberLong":"1656009267652"}}},{"score":81.77466359705439,"time":{"$date":{"$numberLong":"1656009267680"}}}]}]

db.collection.aggregate([{/** limit docs*/"$match":{"is_team":true}},{/** set MaxScore*/"$set":{"MaxScore":{"$max":"$submissions.score"}}},{"$project":{"_id":0,"name":1,"MaxScore":1,"time":{/** get time at MaxScore*/"$arrayElemAt":["$submissions.time",{"$indexOfArray":["$submissions.score","$MaxScore"]}]}}}])