RAX120 slow wireless download speed (24Mbps) with High Internet Speed (325Mbps)

Following as I'm having similar issues with my RAX120, and have since the purchase date just over 90 days ago. On the latest (1.0.1.100) firmware.

We have gigabit internet with Comcast. Direct modem speed test is > 920mbps. Speed test on (awful) Nighthawk app is similar. 

Assuming we're talking the same language... When my QOS is enabled (WMM on 2.4 and ghz anyway), I get ~30mbps / 400mpbs wireless, respectively. Wired network speeds slow, especially on my TVs (a new LG OLED and Samsung QLED), which hardwired become unusable for streaming. Disabling QOS (WMM) limits the wifi speeds to a crawl, but now the TVs show 96mbps download speed on a Netflix speed test. (I assume the TVs have 10/100 network cards?)

Enabling WMM brings the wifi speeds back up, but kills the wired speed.

Enabling upload QOS doesn't seem to work, as the interface takes around 2 minutes to reboot, but the box remains unchecked.

I tried browsing / utilizing the "hidden" QOS menu but I don't understand what QOS Fasttrack VS service options are.

We have AX disabled and traffic meter disabled.

My whole house is wired, and I'm extremely dissapointed in the flaky performance of this router. On the plus side... every wireless device on every floor receives a good signal.