Database
[{_id:ObjectId("638f5f7fe881c670052a9d08"),list:[{propertyToUpdate:"oldValueToAssign",time:ISODate("2022-11-22T06:30:49.000Z")},{propertyToUpdate:"oldValueToAssign",time:ISODate("2022-11-25T15:30:00.000Z")}]}]
Query
db.collection.update({_id:ObjectId("638f5f7fe881c670052a9d08")},[{$set:{list:{$cond:[{$eq:["$list",null]},null,{$concatArrays:[{$cond:[{$gt:[{$size:{$ifNull:["$list",[]]}},1]},{$slice:["$list",0,{$subtract:[{$size:"$list"},1]}]},[]]},{$cond:[{$gt:[{$size:{$ifNull:["$list",[]]}},0]},[{$mergeObjects:[{$ifNull:[{$last:"$list"},{}]},{propertyToUpdate:"NewValueToAssign"}]}],[]]}]}]}}}])