@Marvin_S it turns out the AX11000 internal speed test is incorrect. When I run Speedtest on my cell phone, I get much faster upload results. I don't know why the internal Speedtest is so far off.

My upload speed has suddenly decreased. I am on AT&T 1Gig network. The AT&T modem shows 900+ speeds for both. I'm using a CAT6 3 ft cable to connect. QOS is off. Internet Port Negotiation speed is...