Apple released a feature called “Time to Walk” for Fitness+. They’re almost like podcasts with a built-in workout feature. On your Apple Watch, you open the Workouts app and choose the Time to Walk episode you’d like to listen to. It will play directly from your Watch to your AirPods or other compatible headphone.
Each episode I have enjoyed is really well done. The speaker is also walking, so you can hear a bit of their surroundings like crunching snow or chirping birds. The speaker
I have run into a few bugs downloading & playing back the content, but otherwise the audio itself is a really great motivator for taking a walk.