@Antonio89 

For the speed issue, with main Deco connected to the modem only, you can connect your smart phone or computer to the Deco wifi network and run the speed test for 3 times.

Meanwhile, please click here to check the wireless negotiation speed on your device. Please notice that the actual speed equals 60% of the wireless negotiation speed, and considering the interference/obstacles, the actual speed will be lower. So compared to the varied wireless negotiation speed, the current wifi speed seems normal. 

For the 2.4GHz detected by the wifi analyzer with 2.4GHz host network disabled, it is used for the wireless backhaul among the Deco units. It won't be detected by the regular wireless devices.