Here the resolution on this. I did finally get my bag back 4 days later.

I did try contacting the lost & found. It was easy to file something online. Didn't really help much.

I placed numerous calls to Delta. A few observations:

1) They were easy to reach; I never had to wait long.
2) Of the dozen or so calls, 10 of them were very friendly and professional.
3) They have a system that makes it difficult on the phone agents. All they can do is send a message to the airport, and they do not receive a response. And they are only allowed to send one message per day.
4) I finally found one person who was willing to place my call on hold and actually call the airport. Not sure if it was coincidental, but at that point things started moving.
5) There was NO communication back from Delta on this. I would call in and perhaps every 3rd call would learn a little something as the agent would read some notes. But Delta never proactively kept me informed. They never even informed me once they had recovered the bag and forwarded it to my home airport. I found out when I checked my TILE (the android Airtag) the app reported that it was back in my hometown.
6) Delta did confirm to me that in the event of a loss that they would responsible, even with this unusual situation.

What eventually happened was that the bag was returned to Cathay Pacific. They only have one flight in and one flight out per day, so they are not staffed around the clock (which I explained to the Delta phone agent). I think the call that was made on my behalf helped to inform the YYZ baggage desk of that limitation and that's what eventually got things moving. Had this been with a carrier operating more flights, I might have gotten my bag pack quicker.

The bag came in on a 7:30PM flight. They didn't deliver it until the next afternoon. It was a bit of a concern as it was picked up by some unknown delivery service (with unknown security) who kept my bag overnight. The bag was returned filthy and broken beyond repair. Delta has been responsive so far about the bag replacement, but it's still not completely resolved. There were things missing from the bag; Delta was very good about that.

Now I know how to transfer the bags in YYZ if I ever pass through again. A little bit of signage and better trained baggage staff could have saved a lot of grief and cost.