The developer working on integrating network display functionality into GNOME Shell shared short video clip to the GNOME sub-reddit [...] the feature adds a “screencast” button to the row of actions in the Quick Settings menu. Clicking this opens a modal picker where the user can select any Miracast or Chromecast compatible displays on the network.
You’re right, but the AirPlay protocol has been updated over the last 9 years. I found something called UxPlay and it works pretty well. https://github.com/FDH2/UxPlay