Combine Multiple APs into One Seamless WiFi Network: Setup, Tips, and Unify Advantages

Hello, it has been 5 years since the post was published. Need a similar solution. What has changed in technology over these few years?
All AP devices will be connected by wires. I need to splice a dozen sonoff devices running on 2.4GHz. I am wondering whether Mesh or 2 additional APs with different SSIDs. Which will work better ?

Posting on a new topic, but...

monter79 wrote:

I have to splice a dozen sonoff devices running on 2.4GHz

IoT for the poor (I have Tuya too, to be fair) is fussy. It doesn't often cope with WPA3 enabled networks and PMFs that are in new generations of APs.

monter79 wrote:

I am wondering if Mesh or 2 additional APs with different SSIDs. Which will work better ?

"MESH", then only as an AP, that is MESH with Ethernet Backhoul. But you need to find models that have support for multi SSID (Home, Guest) and a third dedicated SSID in compatibility mode for IoT (WPA2 only, PMF disabled).
Personally, I'd look around for a Unifi U7 Lite and put the necessary SSIDs on that (and split the network into VLANs if possible). Particularly as allowing such poor IoTs into the main, internal network, with a connection to no one knows where and with a hole in the software, is not a good solution.