@UGORE,

The speeds that you are actually able to achieve in your home are highly dependent on the environmental conditions; however I would believe that the falloff is just a % falloff so restoring your ISP to gigabit service will also serve to improve the speeds at those distances. I would assume also that you will not receive the full speeds at the maximum distance, especially if wirelessly networked together, rather your devices will maintain a more reliable connection as the distance increase.

A few things to try:

Does the overall speed of the network increase when you move the WAN connection to one of the 1Gbps Ethernet Ports?

Do you have any QoS settings enabled for the Deco network?

When testing your speeds, are you testing through a wired connection such as a PC; the overhead that comes with wireless connections can cause the readings on phones or in the Deco App to be inaccurate. Are the speeds the same when tested through a wired ethernet connection?