Additionally, some of the devices are just being disconnected. IOT network has 18 devices and normal network another 20.

@David-TP  additionally, I have just upgraded firmware on both units to version 1.2.8 Build 20240328 Rel. 43136, but the issue still persist. Multiple devices on Wifi 6 5GHz are sufferring from very low speed 7/7 Mbps and internet is basically not working at all. Is there any way how to fix it please or should I consider returning the unit and keep M9 Plus as AP's?

Thank you!

Hi  @David-TP ,

thank you for the suggestion. I cannot disable 2.4 because many of the devices in IOT are relaying on it. I did check the mesh and disabled it as well as beam forming. So far it looks better, I think. About the slow speed on 5GHz - I have noticed that this behavior is happening when TV is on. TV is connected through the RJ45 to the backhaul unit as well as another device. That means all 3 ports are used. 1x2.5 for connection with main and 2x1 for TV and another device. Once TV is switched off problem disappeared. The issue is happening across multiple devices PC with W11 and two Android phones. Are you aware about such issue caused by utilizing all three ports?

Thank you.

  @Pecaaa How do you monitor the ping of your Decos in Home Assistant? Any Integration or Plugin? Graphic looks like Grafana but I'm not sure

Btw did you tried using WiFi 6E Band as Backaul istead of Ethernet and compare performance? Maybe your Ethernet link have some interfrences 

  @Xeberth 

Hi, I am using ping feature in HA to monitor both the main and one connected via backhaul. Graphics is done by custom mini graph card. Connection is done through STP CAT6 so there should be no interference. I found out that the issue is caused by LG soundbar which is using its own WiFi and interfering with 5GHz network. So far I could not find a way how to get rid of this..