How to differentiate bewteen begins with and contains in mongo Atlas using regex

Question

I want to boost my score for begins with the case. For example _ I have below two records.

HCL2% CRM
DETHRANAOL HCL CRM

I need a score of HCL2% CRM more than DETHRANAOL HCL CRM when searching with HCL for expected results.

I am trying regex ^HCL(.*) so that it matches with HCL2% and then I will boost its score but this regex is not working in the mongo atlas query.

Can someone help?

Below is the query I am using.

db.compound.aggregate([
  {
    $search: {
      "index": "compoundSearchIndex",
      "compound": {
        "should": [
          {
            "autocomplete": {
              "query": [
                "HCL"
              ],
              "path": "name.en",
              "fuzzy": {
                "maxEdits": 2,
                "prefixLength": 1,
                "maxExpansions": 10
              }
            }
          },
           {
            "regex": {
              "query": [
                "HCL"
              ],
              "path": "name.en",
              "allowAnalyzedField": true,
              "score": {
                "boost": {
                  "value": 30
                }
              }    
            }
          },
          {
            "regex": {
              "query": [
                "HCL(.*)"
              ],
              "path": "name.en",
              "allowAnalyzedField": true,
              "score": {
                "boost": {
                  "value": 10
                }
              }    
            }
          },
          {
            "regex": {
              "query": [
                "(.*)HCL(.*)"
              ],
              "path": "name.en",
              "allowAnalyzedField": true
            }
          }
        ],
        "must": [
          {
            "equals": {
              "value": true,
              "path": "active"
            }
          }
        ],
        "minimumShouldMatch": 1
      }
    }
  },
  {
    $project: {
      
      "name": 1,
      
      "score": {
        $meta: "searchScore"
      }
    }
  }
]);

Answer 1

Using lucene.keyword analyzer instead of lucene.standard solved the issue.