get lead value based on rankings

I'm trying to get the lead value based on rankings. Example: for rank #1 (using rank window function), I would need the value of a certain column for rank#2. My problem is, if there's a tie in rank#1 (like 2 rows tied at rank#1) the prior value that i'm getting for row#1 is correct (column value of rank#3) while the prior value on row#2 is getting null.

sample data
rankings, employee, col_date,     job, col_a, col_a_date
1        john smith  2022-05-12   a    abc    2022-05-12 
1        john smith  2022-05-12   b    def    2022-05-12 
3        john smith  2022-03-27   a    ghi    2022-03-27 
4        john smith  2021-09-21   a    abc    2021-09-21

What I'm getting - actual result
rankings, employee, col_date,     job, col_a, col_a_date, prev_col_a
1        john smith  2022-05-12   a    abc    2022-05-12  ghi
1        john smith  2022-05-12   b    def    2022-05-12  def
3        john smith  2022-03-27   a    ghi    2022-03-27  abc
4        john smith  2021-09-21   a    abc    2021-09-21  <null>


Expected result
rankings, employee, col_date,     job, col_a, col_a_date, prev_col_a
1        john smith  2022-05-12   a    abc    2022-05-12  ghi
1        john smith  2022-05-12   b    def    2022-05-12  ghi
3        john smith  2022-03-27   a    ghi    2022-03-27  abc
4        john smith  2021-09-21   a    abc    2021-09-21  <null>

For both rankings #1, i want to get the value of col_a of the next rank which is rank#3.

select *, lead(col_a,1) OVER w as prev_col_a
from (select RANK() OVER (PARTITION BY  employee ORDER BY col_a_date DESC) rankings,
      *
      from table
) WINDOW w AS (
        PARTITION BY employee, job
        ORDER BY col_a_date DESC
    )
  order by rankings, col_a_date desc