Setting up Elasticsearch _score based on the field value in relation to another field value of the corresponding document

Question

We are updating our search engine from Solr to Elasticsearch. We have already improved a lot of things, but something still did not work out, it is increasing the rating of the document (product) by the popularity of the product (this is an e-commerce website).

This is what we currently have (with lots of irrelevant bits):

{
    "query": {
        "function_score": {
            "query": {
                "multi_match" : {
                    "query":    "renal dog food",
                    "fields": [ "family_name^20", "parent_categories^2", "description^0.2", "product_suffixes^8", "facet_values^5" ],
                    "operator":   "and",
                    "type":       "best_fields",
                    "tie_breaker": 0.3

                }
            },
            "functions": [{
                "script_score": {
                    "script": "_score * log1p(1 + doc['popularity_score'].value)"
                }
            }],
            "score_mode": "sum"
        }
    },
    "sort": [
        { "_score": "desc" }
    ],
}

The field popularity_scorecontains the total number of orders containing this item in the last 6 weeks. Some items will never be ordered, and some will have 30,000 (with potentially much more as we continue to grow our business). This is a fairly large range.

, () , . , , , . , , - popularity_score popularity_score , (log1p ). - ?

!