Here is the JSON for this:

      "and": [
        {
          "attribute_compare": [
            "embed.external.title",
            "!=",
            "x.com"
          ]
        },
        {
          "regex_negation_matches": [
            "text",
            "\\b(x\\.com|twitter\\.com)",
            true
          ]
        }
      ]
    }