HomeKit and Airplay 2 over mesh Wi-Fi problems

I’m trying to determine the source of my HomeKit and airplay problems:

difficulty connecting phone to some home pods or making several rooms play the same thing. Sometimes it works and other times not. Usually if I restart everything it works for a bit. Also giving Siri commands to a HomePod for devices in other rooms sometimes doesn’t work too.

my network is a Bell Homehub 4000 with a Plume Superpod mesh extender. The problem could be simply the mesh network. Or the 2.4/5 ghz or something else. Ideas?