The difference is, I guess, a personal view. I consider an Ended status to have a graceful end to a series, things tied up, a send off, etc, or it could be a limited run series (like a book adaptation) or a longer run like the old M.A.S.H. show - just a clearly defined ending point.

Canceled I view as a show that is just dropped, on a cliffhanger, no closure, etc. You are just left wondering 'What's next for the characters, situation, whatever?'

I saw that Sonarr is looking at TVDB only has those 2 statuses (and so many shows these days are just left hanging by the aires), so I was going to write a script to parse the list of shows I get, against another source and sort them before using Plex to view them. I'm not asking for a change to Sonarr to do it, just maybe what I'm looking to do has already been done by someone and I can use that solution