Improving query performance to search in clob column in big table - oracle

Question

I have a big table (about 4.6 million records) with many columns, I have concatenated some columns and inserted it in clob column(one column have an alias of the name so the name came in a different way and it inserted in clob column )and that column with ctxsys.context index.
I searched with contains a function with the fuzzy operator and for performance, I added tow columns to search and those columns with a bitmap index
and analyzed the table by using DBMS_STATS.GATHER_TABLE_STATS() also I alter my index to take parallel with 4 degrees and increase SORT_AREA_SIZE to 8300000.
My problem is when I searched it's taken from 2 to 5 min to executed.
is there any way to improve performance and reduce time execution(another algorithm to speed searching or I can change the structure of my table by increase the columns and search in multiple columns).
Here is my query:
SELECT first_name,
last_name,
countries,
category,
aliases
FROM (SELECT first_name,
last_name,
countries,
category,
aliases,
rr
FROM (SELECT T.u_id,
T.first_name,
T.last_name,
T.countries,
T.category,
T.aliases,
ROWNUM rr,
all_data
FROM tbl_rsk_list_world T
WHERE t.countries = 'SPAIN'
AND category = 'Eng')
WHERE Contains(all_data, 'fuzzy(JOSE,60,,weight)', 1) > 0)
WHERE rr BETWEEN 1 AND 500
The Execution plan is:
SQL> select * from TABLE(DBMS_XPLAN.DISPLAY);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 2747287528
--------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 20651 | 109M| 5724 (1
|* 1 | VIEW | | 20651 | 109M| 5724 (1
| 2 | COUNT | | | |
| 3 | PX COORDINATOR | | | |
| 4 | PX SEND QC (RANDOM)| :TQ10000 | 20651 | 4638K| 5724 (1
| 5 | PX BLOCK ITERATOR | | 20651 | 4638K| 5724 (1
|* 6 | TABLE ACCESS FULL| TBL_RSK_LIST_WORLD | 20651 | 4638K| 5724 (1
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("CTXSYS"."CONTAINS"("ALL_DATA",'fuzzy(jose,60,,weight)',1)>0 AND "
AND "from$_subquery$_002"."RR">=1)
6 - filter("COUNTRIES"='SPAIN' AND "CATEGORY"='Eng')
20 rows selected
when I using FIRST_ROWS and DOMAIN_INDEX_NO_SORT hints the execution plan be:
SQL> select * from TABLE(DBMS_XPLAN.DISPLAY);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1488722846
--------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 50 | 173K|
|* 1 | VIEW | | 50 | 173K|
| 2 | COUNT | | | |
| 3 | TABLE ACCESS BY INDEX ROWID| TBL_RSK_LIST_WORLD | 50 | 11500 |
|* 4 | DOMAIN INDEX | NDX_RSK_LIST_WORLD_CTX | | |
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("CATEGORY"='Eng' AND "COUNTRIES"='SPAIN' AND
"from$_subquery$_002"."RR"<=500 AND "from$_subquery$_002"."RR">=1)
4 - access("CTXSYS"."CONTAINS"("W"."ALL_DATA",'fuzzy(jose,60,,weight)',1)>0)
18 rows selected
but still the performance bad :\