@rcaridade That's a common problem with WiFi IoT things, routers are not able to keep so many WiFi connections (they usually start to struggle when managing more than 30 connections)

Zigbee and other protocols handle this scenario better, I find WiFi fine for few devices only because you don't need a bridge. But taking into account most IoT devices are usually bulbs and switches, going Zigbee is usually better because it is a standard and doesn't even depend on the provider cloud.

I don't know if in OneMesh you can force a device to connect to a specific extender, that would be a solution, to have them distributed. Maybe they're all trying to connect to the same.

You may need an additional access point or two with different SSIDs so you can control where each device is connected. They can be cheap 2.4GHz APs, no need for high bandwidth usually in those devices.

Or get a better router/APs or system, again, I don't know if OneMesh, Deco systems or AiMesh allow to distribute devices automatically or manually.