https://thenextweb.com/apple/2019/04/08/heres-why-you-cant-use-airplay-with-netflix-right-now/

Last week, Netflix removed support for AirPlay from its platform. That means you can’t beam Netflix shows from your iPhone or iPad to your Apple TV.

Instead, you’ll have to rely on the Netflix app for Apple TV, and use the remote for the set-top box to navigate the platform. Boo.