R7000 Drops wifi for all devices only when certain devices connect

Hello,

I have owed a nighthawk R7000 for many years and it has always performed very well. Recently, the Wifi becomes unavailable and I have to reset the router. This occurs *only* if my FireTV stick or my Samsung TV attempt to connect to the router. Strangely, both of these devices have connected successfully for as long as I have owned them. This has only been an issue in the past few days.

All other devices work flawlessly. Two Mac Book Pros, two Echo's, an apple watch, an android phone and an iPhone. The wifi is stable and no issues until the moment I turn on the Samsung TV or the FireTV. Then the wifi becomes unavailable to all devices. A reboot restores wifi but only if I don't let the TV or the Fire stick connect.

I've tried factory reset, multiple times. Both the regular and the 30-30-30 version.

I've also tried to change the firmware. I first updated to what was then the latest: V1.0.11.122_10.2.100. Strangely, I can't change the firmware anymore. When I try to update, it goes through the motions and seems successful, but when I bring up the admin page, it always shows I have V1.0.11.122_10.2.100 installed. I've tried other firmware version multiple times. This includes a newer version (R7000-V1.0.11.123_10.2.100.chk) and the suggested downgrade (R7000-V1.0.9.42_10.2.44.chk).

I can't find any mention of this specific issue - certain devices causing the wifi to drop. If anybody has any ideas for anything else I can do I'd really appreciate it.