Hello BshmntB,
Thanks for asking about the delay in AirPlay in English. We're happy to check this out with you.
Please try these steps:
1. Make sure each Apple device is up to date.
Update your iPhone, iPad, or iPod touch - Apple Support
Update macOS on Mac - Apple Support
2. Make sure the source device and the destination device are connected to the exact same Wi-Fi network
• For Apple TV and Mac devices, disconnect any Ethernet connections.
• Note: A 2.4GHz band typically has a different network name that the 5GHz band broadcast by the same router.
3. Power cycle the source device, destination device, and all network hardware.
4. Forget the network on the source device and the destination device (for Apple TV), then rejoin the exact same Wi-Fi network to test
How to forget a Wi-Fi network on your iPhone, iPad, iPod touch - Apple Support
5. Isolate content-specific issues by testing the WWDC Keynote in Safari: https://www.apple.com/apple-events/june-2021
• Some apps like Netflix don't support AirPlay or AirPlay Mirroring of their content
• Other apps don't supported AirPlay Mirroring with their protected content; AirPlay needs to be enabled from within the app's user interface
• If the issue only occurs with third party apps, content or websites, please contact the app developer and/or content provider:
Contact a third-party vendor - Apple Support
6. If you have a mesh network or a network with multiple access points, disconnect all satellite routers or additional access points so just the main router remains.
• If the issue only occurs when satellites or additional access points are connected, please contact the network admin/ISP or router manufacturer for assistance optimizing those satellites/access points
7. Please let us know if the issue remains using the WWDC Keynote in Safari.
Thanks!