You can set chats to be deleted automatically if there is no activity for a certain period.

  1. Go to Profile → three dots ⋮ → Settings.
  2. Enter Chats.
  3. Enable Delete due to inactivity.
  4. Choose the time (8h, 24h, 7d, 90d).

If there is no activity during that time, the chat will be automatically removed from your device.