Until a couple of days ago, I was able to see the OVERDUE tasks in one of the views (I think it was TODAY view). But now I am unable to see it anywhere. Instead, I have to go thru all on my 200+ tasks to see which one is overdue (which is so dumb). How can I reinstate seeing the overdue tasks in today view?

This sounds odd. Could you please clarify the device you are using and send us a screenshot of this list view?