Deco extremely low wifi speeds
Does anyone know how to increase wifi speeds on the deco M4? Currently we have fiber optic internet with a download speed of 1.06GB and an upload speed of 900Mbps. Due to our house we have quite a few dead zones especially in the basement. When connect to the deco systems in the basement or top floor we can only archive a download speed of 30Mbps, that is including systems that are using an Ethernet connection from the Deco systems. I have bought new cables which can allow for gigabit speeds, I have also changed the Qos on the Deco apps to reflect our wifi speeds from our main modem but still has not changed the speeds. Again does anyone know a solution to this issue?
Update: Deco 1 is located on the main floor which is connected to our main modem. 2 is upstairs in an office, and 3 is located in the basement.
Thank you!