my situation improved when I bought a 14m long telefonic cord and I moved the cordless Panasonic to the opposite end of the room.
It turned out that the 2.4Ghz WiFi of the Archer VR1600v was out of tune, and still is. It was interfering with all devices, even with my cordless mouse and keyboard. So I turned it off and I'm only using the 5Ghz Wifi. In addition, I bought a cheap router, connected it to the Archer and that gives me 2.4Ghz WiFi, in a better location.
I don't want to formaly complain about the Archer VR1600v because other parts of it work well. The internet connection is stable, which is the main thing. If I get a replacement, I might end up worse.