I had a LinkSys WRT32x as a primary router ad a WRT1900AC as a secondary on 1GB fibre service. I had the WRT1900AC setup upstairs as an access point, with settings in both routers mimicked & DHCP turned off on the 1900AC. The 1900AC was plugged into the WRT32X via Cat5 and I could stream 16-18GB HD movie downloads from my downstairs desktop plex server in my basement man-cave without any buffering at very high resolutions. It really was quite impressive although the 5.0GHz band had issues with connection on devices as this wasn't a true mesh system. I decided to upgrade to WiFi6 with an ASUS RT-AX88U which i had read good things about. I instantly noticed connection issues with Plex where it stated a direct connection to my server is no longer established and that quality & compression may affect playback. Sure enough the quality is absolute trash. Coincidentally, the plex App on my Shield where I was streaming to has also just seen a major overhaul so I checked all the obvious settings in plex to make sure it wasn't just an app issue. I also noticed my nest cams throughout the house constantly losing connection to the RT-AX88U, another issue I had zero problems with on the old setup. I also started experiencing printer connectivity issues so all this has to be with the new hardware and it's setup. There's no obvious setting for UPnP on this router so I looked it up and apparently you have to turn on the 'Enable Multicast Routing' under IPTV, this is supposed to enable UPnP. Still no joy. I can't even connect to my plex server at all now, where I could before with just horrible quality transcoding/streaming to TV's. There must be some settings here I'm overlooking that are causing this poor performance from the superior router. I just purchased an Asus GT-AXE11000 that i want to run as primary in the service room in basement then run the RT-AX88U as secondary upstairs to get full signal throughout the house. I just don't have the new AXE router yet. Any help and direction on getting this thing setup right would be greatly appreciated. Thank so much!