I have recently switched from a basic, ISP router to a set of three X20s to improve the range and signal strength.

I have set up multiple devices including computers, iPads, phones, TVs and Apple HomePod mini speakers, all of which are connecting to the network and running fine.
 

However, since switching to this new setup, I'm no longer able to use AirPlay between devices. For example playing music on my phone, iPad or computer through my HomePod speakers or TV. 
 

I have followed advice from other posts to turn off the mesh capability of the network, turn of fast-roaming, set security to WPA2/WPA3 Personal, turn on IPv6 and lock devices to the same X20, all with no results.

Is this problem a result of recent firmware updates, or possibly an issue with Apple AirPlay's compatibility with the mesh system?

Any advice would be much appreciated.