Nighthawk CAX80 (AX6000) defective

I bought a Nighthawk CAX80 (AX6000) on 10/17. I have gigabit internet speed through Comcast. After setup, my wired speeds are maxed at 300Mbps and wifi is maxing at 50Mbps (worse than my previous 200Mbps service). After hours of troubleshooting with Netgear, they said it was Comcast's issue. After a tech was onsite and verified the connection quality. With a different device, they were getting 1,100Mbps speeds.

So I called Netgear support and relayed all the information, only to have the tech then confirm the device is defective. So they set me up with an RMA for the device, said they would ship the replacement to me, and then I can send the defective one back. Days later and no status change on the RMA. So I call in, spend another hour on the phone, only to find out they have no information on teh tracking status.

Can anyone help me. Some kind of alternative fix for the device (firmware is up to date, wifi channels have been changed, MTU has been changed, factory reset has been done multiple times, etc)? Can anyone provide me a different support number to call? Or can anyone help get me through the nonsense techs that I have to re-invent the wheel with each time I call?