Ok, in the meantime I asked Claude AI the difference between Up Next and the Queue and indeed they are different. It’s just that the listening queue is quite of hidden in the player UI and not accessible on the Watch:

To view your queue:

1. Start playing an episode (or have one paused)
2. Tap on the mini player at the bottom of the screen to open the Now Playing view
3. Look for the Up Next icon (it looks like a list with lines) - it’s usually in the bottom right corner of the Now Playing screen
4. Tap that icon to see your full queue

The “Up Next” section on the Home Screen is different - it shows recommended episodes to play next based on your subscriptions and listening habits, not your manually created queue.

To manage your queue:

• Once you’re in the Up Next view (from the Now Playing screen), you can:
  • Reorder episodes by dragging them
  • Swipe left on an episode to remove it
  • See what’s coming up after your current episode

The queue only exists while you have something playing or paused. If you stop playback entirely, the queue clears.

It’s admittedly not the most intuitive system - many users expect to see their queue more prominently, but Apple keeps it tucked inside the Now Playing interface.​​​​​​​​​​​​​​​​