@Tediouspuppet 

Hi, Thank you very much for your time and patience.

Using Deco M4 as the main Deco might be a workaround to break the 100m/s limitation of Deco E4 and it is not always a good idea since we could not use the Ethernet backhaul to improve the speed of satellite Deco anymore.

May I know how long have you had the M4+4*E4? (If they are just newly purchased, maybe you could replace them with a 3*pack wifi 6 Deco, such as Deco X50/X55.)

And How about the specific speed you could get from each satellite E4? and can I have a picture of the network topology/layout?

Using main Deco as the signal source is not a bad thing and due to the working pattern and protocol/regulation of Wi-Fi technology, the more wireless hops, the slower the speed would be.

Thanks a lot.

Best regards.