How to call PostgreSQL procedure inside loop?

I have a procedure like that;

CREATE OR REPLACE PROCEDURE insert_into_tableAv2(inout rows_affected INT) LANGUAGE 'plpgsql' AS $$ BEGIN
    INSERT INTO insert_into_tableAv2 (serial, aaa, ooo, UPDATED)
        SELECT id, aaa, ooo, UPDATED
        FROM tableA
        WHERE NOT EXISTS (
            SELECT 1
            FROM tableAv2
            WHERE tableA.id = tableAv2.serial AND tableA.aaa = tableAv2.aaa
        )
        LIMIT 100;

        GET DIAGNOSTICS rows_affected = ROW_COUNT;
        RETURN;

END; $$;

TableA has 9000 records in my DEV environment. Basically, it's a pretty small table.

When I call it like that it makes RDS CPU %100, and cannot insert anything and timed-out as well.

DO $$
DECLARE
    result int := 0; -- Initialize with a starting value
BEGIN
    LOOP
        result := 0;
        -- Call the procedure and update the result
        CALL insert_into_tableAv2(result);

        -- Exit the loop if the result is 0
        EXIT WHEN result = 0;
    END LOOP;
END $$;

The reason I wrote it like a procedure is that I want to run similar queries in bigger tables and call it many times. So does anyone know why the procedure call is not working ?