There is not set pattern to prepare for CAT. It's a test which evaluates your instincts and presence of mind.
In order to prepare for CAT 2021, I will suggest change your strategy of giving Mocks. Opt for a different test series, for instance if you had taken up test series of career launcher now go for TIME or Tathagat. Identify your areas where in you take more time, analyse mock tests closely (spend around 5-6 hours) and lastly remain calm.
And gap years do not hamper your selection chances.
Hope this helps :)