Gigabit wifi speeds halved on XR1000

I'm sure that this topic gets touched on a couple of times a month at this point, but I cannot find a working solution to this issue. I just moved to a new house and we upgraded to gigabit download speeds. The issue is that my network download speeds seem to max out around 450mb/s. It does not appear to be the modem (which does not have router functionality), as I have tested the ISP provided router which provides 900mb/s at a minimum on wifi and ethernet.

Things that I have tried:

- Factory Reset router

- Disabling QoS as well as resetting distribution, Traffic meter, and congestion control (this did briefly bring ethernet speeds to 900, before returning to 400s)

- Manually setting expected speeds

- Removing all other devices on the network

- Using ethernet (Cat-6)

- Switching Wifi Channels and checking for interfering networks

- Updated to most recent firmware

All of the above were tested at a time that internet congestion would be at a minimum.

Clearly, there is still a setting that I am missing since speeds to the router are at least 900, and the router should theoretically be capable of over 4Gb.

If anybody out there has a fundamental understanding of DumaOS and this router, I would greatly appreciate your insight.