Upload Speed is Garbage - Ridiculously Slow [Edited]

I have a Netgear AX6000 WiFi Cable Modem / Router. I previously lived in an apartment complex that used Xfinity exclusively and had the 1 Gig package. With this service, the upload and download speeds consistently met or exceeded advertised speeds.

I've recently moved and signed up for Xfinity service again, this time with the 2 Gig service, which the modem is rated to handle. While the download speeds averages about 680 Mbps, the upload ranges from 1.7 to 5.7 Mbps consistently - significantly below the package. I've spent hours with tech support via chat, with each rep claiming to be able resolve the issue. None did. Each support episode ends with some variation of, "I've submitted a request to re-provision' your account and you should see improvement (all failed) -- Then, the tech all seem to push using Xfinity' equipment vs my own. I can only wonder if Xfinity purposely throttles accounts where uses opt out of using Xfinity equipment.

Since the 2 Gig package didn't perform as advertised, I reverted back to the 1 Gig - with no change in download speed and still the same atrocious upload speed. Unplugging a modem from one location where it performed remarkably, activating it in a new location, and experiencing degraded performance should indicate it's a location-specific issue vs. the equipment.

Don't know how many more calls I need to make or hours spent via chat to have the issue resolved. IT'S FRUSTRATING - each tech going through the same steps - every time - with the same failed results.