Nighthawk R7000 regularly drops

I purchased a new NETGEAR Nighthawk Smart WiFi Router (R7000) - AC1900 a few weeks ago and I have it configured as an Access Point. Setting it up was a bit odd from the beginning, for example on the Home Page it always says that the Internet is "Not Connected" even though it is. But I got it to work and my direct wired connections give me 800-950Mbps on my 1G service, so amazing. 

Wifi however is really inconsistent. 2.4G is disabled, as is the Guest network, so only 5G is enabled. All other settings are default.

Through 5G on my phone or laptop, standing right beside the AP, I get about 50M, at most. That’s it, 50M. About 5%. Usually it is closer to 20-30M. Standing beside the AP which is direct wired into 1G ethernet.

If I enable WMM on my 5G connection I get 400-460M, amazing, exactly what I should be getting. However, 100% of the time the connection will slowly die until it completely drops. Sometimes it last for 20-30 minutes, sometimes less than 5 mins.

So without WMM my speed is pathetically slow, but with WMM my connection eventually dies.

I have tried the latest firmware version released in Jan/21: V1.0.11.116

I have also tried down-grading to Firmware Version: V1.0.9.42_10.2.44 as it was suggested (in this community) to be the most stable. Both versions have the same issue.