How to get more than 4000 character like LISTAGG?

In case we want to list more than 3999 characters in one column-

SELECT TBL1.COL1,
       SUBSTR(XMLCAST(XMLAGG(XMLELEMENT(E,' | ' || TBL1.COL2)
                                       ORDER BY TBL1.COL3) AS CLOB),
             4) AS COL2
       FROM
       (
          SELECT DISTINCT COL1, COL2
          FROM TABLE_1 TB1,
          TABLE_2 TB2
          WHERE TB1.COL = TB2.COL
       ) TBL1
       WHERE ...
       GROUP BY TBL1.COL1