Slow atlas search query

Hello guys, I have a problem with slow search queries.
I am from Czech Republic and i need Search Diacritic-Insensitive Query
I use custom analyzer according to the documentation
Cluster tier M20
Count of documents: 50 000 000
Index name is: prod-evidence-systemove-zaznamy-fulltext-index-v2
Query takes cca: 200+ seconds
Search term: vytvoren
Query path: podrobnosti

My Golang query is:

func search(db *mongo.Database) error {
	coll := db.Collection("systemove-zaznamy")
	opts := options.Aggregate()

	search := bson.M{
		"$search": bson.M{
			"index": "prod-evidence-systemove-zaznamy-fulltext-index-v2",
			"compound": bson.D{
				{"must", []bson.M{
					{"wildcard": bson.M{
						"query":              fmt.Sprintf("*%s*", "vytvoren"),
						"path":               "podrobnosti",
						"allowAnalyzedField": true,
					}},
				}},
			},
		},
	}

	limit := bson.M{"$limit": 100}

	pipeline := []bson.M{
		search,
		limit,
	}

	ctx, cancel := context.WithTimeout(context.Background(), timeout*time.Second)
	defer cancel()

	cursor, err := coll.Aggregate(context.TODO(), pipeline, opts)

	if err != nil {
		log.Fatal(err)
	}

	defer cursor.Close(ctx)

	zaznamy := make([]SystemovyZaznam, 0)

	err = cursor.All(ctx, &zaznamy)

	if err != nil {
		log.Fatal(err)
	}

	return nil
}

JSON of my atlas search index:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "_id": {
        "type": "string"
      },
      "datum": {
        "type": "date"
      },
      "idSoutezeString": {
        "type": "string"
      },
      "prihlasovaciJmeno": {
        "type": "string"
      },
      "idPredmetu": {
        "type": "string"
      },
      "zdrojovaSluzba": {
        "type": "string"
      },
      "idSoutezeProZadavatele": {
        "type": "string"
      },
      "idCentralizovanehoZadavani": {
        "representation": "int64",
        "type": "number"
      },
      "uroven": {
        "type": "string"
      },
      "podrobnosti": {
        "analyzer": "diacriticFolder",
        "type": "string"
      },
      "ukon": {
        "analyzer": "diacriticFolder",
        "type": "string"
      }
    }
  },
  "analyzers": [
    {
      "charFilters": [],
      "name": "diacriticFolder",
      "tokenFilters": [
        {
          "type": "icuFolding"
        }
      ],
      "tokenizer": {
        "type": "keyword"
      }
    }
  ]
}

Example of document:
{
  "_id": "fcabbf31-7cc5-4f57-a093-e8d099266d75",
  "uroven": "INFORMACE",
  "ukon": "Vytvoření uživatele",
  "prihlasovaciJmeno": "uzivatelz2",
  "datum": {
    "$date": {
      "$numberLong": "1670679519489"
    }
  },
  "podrobnosti": "Uživatel s id uzivatelz1 byl vytvořen a přidán k organizační jednotce",
  "zdrojovaSluzba": "tenderarena"
},

Why is query is too slow?