Hi.  The app is just a remote control so there is little that can go wrong with the app itself.  The apps just give you a picture of what is there in the system, so it’s particularly odd that some stereo pairs appear as broken in one app but not others.  Could you provide a bit more information about your network?  Router, whether mesh, any extenders etc?  Dual band?

I am using 14.18 on Android with no problem, so it doesn’t look like a generic problem.

I have an AVM FRITZ!Box 7530 router with different SSID for 2.4 and 5GHz networks. There are no Wi-Fi extenders nor mesh as the Wi-Fi coverage is excellent.

Sonos is configured for the 2.4 network and gets static leases from the router’s DHCP server.

That’s all…

And yep, I know it’s odd, but both macOS and iPadOS controllers work smootly. 

@alebissoli, I’ve got a Fritzbox. Its interface is in German though, therefore I am not certain about the correct translation.

Within the tab ‘WiFi security’ (?) there is a setting called The WLAN devices displayed may communicate with each other → enable it, if it is disabled.

Sonos require unrestricted internet access. If you have assigned any restrictions undo it.

https://en.avm.de/service/knowledge-base/dok/FRITZ-Box-7530/8_Restricting-internet-use-with-parental-controls/

Set the wireless channel to either 1, 6 or 11. If its bandwidth is set to 40 MHz change it to 20 MHz instead.

If you have a HUE bridge, set it to channel 25 or 26.

See also Reduce wireless interference

Which band(s) do the Mac, iPad and Android controller connect to?

I would be interested to know if the problem persists if you connect just one of your speakers to the router by Ethernet (as an experiment).

Just for info, my Android app is still working fine.  I think the problem is likely to have a local cause.