<125 Mbps on an 800 Mbps Plan

Since moving to Xfinity, I have never received the speeds of my plan.

I have talked with support agents multiple times and have had a technician come to my house. After that visit, the technician said it was my devices and suggested that I use Xfinity's devices instead. I'd rather use my own and the previous device we rented from Xfinity didn't work either. I bought a new, non-OEM router and modem (modem was on the approved device list and I activated it through my Xfinity app):

ASUS Router RT-AX3000
Motorola Modem DOCSIS 3.1 (w/ 2.5 Gbps Ethernet Port)

I want to emphasize the following summary: my equipment is not the problem. I have tested it at a friend's with a different cable Internet provider and have received expected speeds.

After further calls, no one can explain my issue. Many Xfinity agents suggest another technician come to my home and test again. I'm not paying for another technician to say yet again that it is one of my devices. It's not my devices nor is it the coaxial cable in my home either (I have checked personally with a handheld device).

With my equipment, I should be able to support 3x the speed of my plan. Testing on the browser, I always get download speeds less than 150 Mbps wired. I know this is accurate, because sometimes my work video chat goes out, complaining of network bandwidth issues. I am part of the 800 Mbps plan and only live in my home with my wife. She doesn't download anything and might on occasion watch Netflix. No massive uploads either. The point is that I should not even be seeing network bandwidth issues if I am to get my paid speeds.

When I test speed through my router diagnostics screen, it always reports expected speeds. My assumption is that it is a direct communication from router to ISP to the Ookla service; therefore, it is a much more reliable tool for measuring potential speeds rather than actual speeds.

Furthermore, I looked at my channels and the RF chatter of my modem connection. I did notice the downstream power levels are a little higher than normal (should be between -8 dBmV to +8 dBmV correct??) and OFDM PLC has a ton of corrected frames. In fact, if you let it run for a day, it'll go negative. Unfortunately this is all controlled by Xfinity and I have no control over it.

No events in the event log out of the ordinary.

Please, get me in contact with someone who can fix my Internet. Again, I'm not paying for a problem with your service and hardware. Besides I'm sure I'm not the only one in my neighborhood that has these problems. There is nothing wrong with my devices or the coaxial cable. I heard that it can sometimes be the node (servicing the neighborhood) or Xfinity throttling my traffic. Either way, I'm not getting what I'm paid for and am very upset.

Finally, I work from home. This speed decrease has been hurting my ability to do my job.

Sincerely,
Scott [Edited: "Personal Information"]

P.S. I don't need to restart my modem, or router, or computer, etc. I have already ran through the typical script and nothing seems to resolve my issues. I just want someone to fix my Internet without charging me for the privilege.