[{"_id":ObjectId("660269c42c04edea870276d6"),"skills":[{"label":"painting","level":8},{"label":"acting","level":15}]},{"_id":ObjectId("660269c42c04edea870276d5"),"skills":[{"label":"painting","level":9},{"label":"dancing","level":15}]},{"_id":ObjectId("660269c42c04edea870276d4"),"skills":[{"label":"painting","level":10},{"label":"singing","level":5}]}]

db.collection.aggregate([{$set:{sortField:{$first:{$filter:{input:"$skills",cond:{$eq:["$$this.label","painting"]}}}}}},{$sort:{"sortField.level":-1}},{$unset:"sortField"}])