My windows devices have been unable to receive a usable download speed when connected wirelessly or wired through ethernet. The upload is great and latency to servers is normal as well. When plugged directly into my modem I receive optimal speeds. A friend of mine connected to one of the deco devices with ethernet on his linux laptop and everything worked fine along with my cellphone, roku tv, and playstation. 

Another weird thing is when testing my speeds on speedtest.net I get a decent download speed (100Mbps-160Mbps). My task manager also shows those speeds when I am testing it on that website. All other speed test sites don't even crack 1Mbps. When trying to download something in practice on Steam, Epic Games, or Microsoft Edge it either fails to download or is fluctuating between 50Kbps-1Mbps. 

I have restarted the devices, had my ISP come to investigate, messaged a representative on the tp-link website, messaged windows IT and had them remotely control my computer to try and fix it twice, installed the latest driver for Realtek PCIe GbE Family Controller, Messed with my security settings, Done a network reset on my PC, Etc. 

Nothing has worked to make my or anyone else's windows devices receive proper download speeds.