Search all fields in elastic 7.x from 5.x

Hi we are migrating from Elastic 5.x to 7.x. And one of the breaking changes is the removal of _all field in match query. Previous query looks like below where its doing search on all fields.

v 5.x

    GET /my_index/_search
    {
      "query": {
                  "match": {
                      "_all": {
                          "query": "hello"
                      }
                  }
              }
    }

What is the best way to do the same in v 7x?

    GET /my_index/_search
    {
      "query": {
                  "query_string": {
                      "query": "hello" 
                  }
      }
    }

OR

    GET /my_index/_search
    {
      "query": {
                  "multi_match": {
                      "query": "hello",
                      "fields": ["*"]
                  }
      }
    }

or is there another recommended way?