Asus mesh network, another router for incompatible devices?

Hi,

I have an Asus mesh network made up of three routers (RT-AC5300 and two ZenWiFi AX). All of our home devices play nicely with the network with the exception of:

Meross Garage Door Opener
Sonos

Rather than having to disable features such as WiFi 6 to make these devices play nicely with my mesh network, would I be better of connecting another (fourth) router and setting up a basic 2.4 GHz network for these devices? I assume I could just plug the fourth router into one of the ethernet ports on any of the Asus routers and set up as a new network? Any potential issues?

It is rather annoying that there are still compatibility issues 🤷🏻‍♂️

Strictly, don't you have one router and two access points?

I have just bought some kitchen appliances that have WiFi connection to phone apps. I made a desultory effort to use them and found similar problems in that the appliances will only 'work' over 2.4 Ghz and 2.4 Ghz alone. They seem to get an IP address when using 5 GHz but won't do anything with it. I struggle to understand how they could even have coded it so badly as to do this and I am concerned what other network-related horrors might be lurking. I don't really feel confident that the appliances aren't a mess of unpatched exploits.

I might use a separate SSID to see if I can get them to do something but, to be honest, the app reviews are amongst the worst I've ever seen. If I do, I might try an old range extender. It's also possible that the app will require to use the same SSID as the appliances which would be inconvenient to say the least.

If I'd bought the appliances because they were ostensibly smart, I'd be furious.

RE Sonos, we have experienced this issue (on BT SmartHub 2 around a year ago). What fixed it for me was to disable 5GHz, connect the Sonos (forcing it to use 2.4GHz details). I then reenabled 5GHz and it seemed to stick to 2.4GHz just fine.

An alternative, if you have several Sonos devices, wiring one of them into either the main router or a mesh point (most of them allow ethernet bridge). You then have internet to the wired in Sonos. At this point you can use SonosNet (Sonos proprietary mesh) to link all others. This avoids having any issues with your WiFi setup given the Sonos devices have, what I would describe as, ancient WiFi standards .