Filter with criteria before sum aggregation

Hey everyone! I'm having a hard time with the following issue. Suppose I have the following three documents:

 {
     "entity_id": "A",
     "stringField1": "SF1A",
     "stringField2": "SF2",
     "numericField": 10,
     "updated_at": "2020-10-18", 
 }
 {
      "entity_id": "A",
      "stringField1": "SF1A",
      "stringField2": "SF2",
      "numericField": 1000,
      "updated_at": "2020-11-18", 
 }
{
      "entity_id": "B",
      "stringField1": "SF1B",
      "stringField2": "SF2",
      "numericField": 1000,
      "updated_at": "2020-11-18", 
 }

I'd like to run an aggregation of numericField values for example for a specific value of stringField1/stringField2 but ONLY considering the "newest" document for a given an entity_id.

I read here about field collapsing here, and it worked if I want to do a term query.

If e.g. I wanted to aggregate for stringField1 == "SF1A" and stringField == "SF1B", I could do:

 "aggs": {
     "first_agg": {
         "aggs": {
             "my_numericfield_agg": {
                 "sum": {
                     "field": "numericField"
                 }
             }
         },
         "filter": {
             "term": {
                 "stringField1": "SF1A"
             }
         }
     },
     "second_agg": {
         "aggs": {
             "my_numericfield_agg": {
                 "sum": {
                     "field": "numericField"
                 }
             }
         },
         "filter": {
             "term": {
                 "stringField1": "SF1B"
             }
         }
     }
 }

But this would consider all (old and new) documents for the same entity_id.

Is there a way to do this aggregation but only considering the latest (by "updated_at") document per "entity_id"? (This is before doing the sum aggregation)

I've read about top hits here but couldn't figure out yet how to apply it to my use case.

Thank you very much!