Hi,
Thanks again for looking into this in so much detail!
The beosound a5 is a semi portable speaker a bit like a sonos move. We bought it to replace a sonos move we had in the kitchen which would try to connect to an access point based on the loft, the furthest away from the device. We hoped the B&O being so expensive would work perfectly. Sadly not the experience so far.
Anyway, it’s wireless because it only has a usb-C socket, I think only for charging. Everything else is now wired.
This morning I took out another router which was operating as a mesh access point so we’re only running the two rt6600ax and the one wrx560. These are all the newer models so maybe that in combination with less access points will reduce the interference.
I also managed to end up with two Internet connections via two isp’s. The first one was slow so we changed but couldn’t cancel. I found out that if I used load balancing across these the roon server would sometimes disappear from the network. I just have the second wan access as failover now, which seems to work better.