Was this ever resolved? There have been others with same exact issue, but have never seen a reslution. I too have a new AX1500 that has worked wonderfully until the 10/28 firmware update. We have done much testing on our end and sure enough, like another post not only is the range now limited, our WIFI drops often. My boys are back to gaming with a LAN cable because their wifi drops so often. I also tried downgrading to both available firmware updates and like others who have tried, neither worked. I get the "unable to upgrade" message for both versions. 

This issue really needs to be resolved. We started having issues the night we did the firmware update.