[{_id:ObjectId("62bf2315503e821576e53c53"),foodName:"food name",foodPrice:"17",category:"sweets",foodDesc:"this is some random text",foodToppings:[{toppingName:"a",toppingPrice:5},{toppingName:"b",toppingPrice:3},{toppingName:"c",toppingPrice:5}],foodTags:["a","b","c"],createdAt:ISODate("2022-07-01T16:38:45.935Z"),updatedAt:ISODate("2022-07-07T10:56:44.447Z"),__v:0,foodImgs:[{foodImgDisplayPath:"https://fakepath.png",foodImgDisplayName:"img_name-0"},{foodImgDisplayPath:"https://fakepath.png",foodImgDisplayName:"img_name-1"},{foodImgDisplayPath:"https://fakepath.png",foodImgDisplayName:"img_name-2"}]}]

db.collection.update({},[{$set:{foodImgs:{$reduce:{input:"$foodImgs",initialValue:[],in:{$concatArrays:["$$value",[{"$mergeObjects":[{data:"$$this"},{inx:{$size:"$$value"}}]}]]}}}}},{$set:{foodImgs:{$filter:{input:"$foodImgs",cond:{$ne:["$$this.inx",1]}}}}},{$set:{foodImgs:{$map:{input:"$foodImgs",in:"$$this.data"}}}}])