Every time I start a new ride on Apple TV, there are no other riders.
The workaround for this is to kill the Zwift app from the task switcher, then re-launch the app (losing any power I might have assigned).
I realise that there is an historic issue where users say there are no other riders, and the cause is a bad internet connection – I do not think this is the case here, as the above workaround always works, and other apps and devices have no problem with the internet connection.
Feels like the Apple TV app has a bad time starting a ride if it has been suspended (not killed) from a previous day. Occasionally not noticing world changes, and dumping me in the wrong course (only happened a couple of times).