If the issues started after they did service in your area, it could be an issue with their network. Not your equipment. Google PING TEST and TRACERT to learn how to run a couple simple tests that will determine if the issue is outside your home. Save the screenshots for proof.
Most technicians will avoid this since Cox doesn't want documented proof of their infrastructure issues. Don't let Cox blame you for their service issues. It took a complaint with FTC and FCC after 6 technicians came to my home in 6 months to show that the issue was with a the south west region [ langbprj02-ae1.0.rd.la.cox.net .]
Run tests through out the day, and If your result show packet loss and drops on THEIR end, you can submit a complaint form to help get the changes made.
sorry for the late response, have been busy working
UPDATE: Cox does see see packet loss and slow speeds on their end, I don't feel a constant 1/3 of the upload I pay for is unreasonable, but they don't seem to care
2 techs have came so far, Tech 1 shrugged it off as noise on the line and said a bucket truck needed to come out, Tech 2 saw 5mb upload and packet loss on his handheld, and scheduled a bucket truck to test tap and lines for noise/ingress, both tickets were automatically cancelled due to "ongoing network maintenance in my area", and still has not been looked into
Field Supervisor came out, he ran the Ookla speed test on his phone and saw 940+ mbps down / 35+ mbps (with the biased Cox pathed New Orleans server, while it was storming outside), he looked at everything up to the pedestal, said it should be tested for noise/ingress like tech 2, and planned to do so when he had free time, but weeks later it still has not happened
I ran OBS for the majority of a week set at 6 mbps with nothing else open and it was able to maintain that 99% of the time while reporting my daily results to him
However the speeds still randomly drop back down horrible briefly and recover, and no one can explain why I see hundreds of thousands of uncorrectable codewords across all channels
when running right: Streaming services on TV display in 4k, PC at 1080p/1440p if available for the content non Cox biased tests show within reason of the advertised speeds (900+ mbps down / 30+ mbps up) the Twitch bandwidth test tool shows 7-10 mbps to all servers, 75+ connection quality to all servers OBS, and Twitch Studio suggest 1080p/720p/60 fps at 6 mbps
when running bad: the cox biased test will go as low as 300 mbps down 8 mbps up Any non Cox speed biased test goes as low as 200 mbps down 2 mbps up the Twitch bandwidth test tool drops to 1-3 mbps results, and 0-30 connection quality and both software will suggest 480p/30 fps at 1-3 mbps with no game open I have tested streaming with Youtube when the internet is running bad and also suggest low resolution / frame rate / bandwidth, so it isn't just Twitch Streaming/Airplay will start drop to a low resolution on TV and PC some times sending pictures and video are slow, regardless of what service and devices
I have upgraded: motherboard from b550 to x570 with a different Ethernet Controller capable of 2.5 GB speeds processor from 5800x to 5950x and have tried different model of ram this is a fresh windows install with all drivers up to date,
there is usually only 2 devices max are using the connection at a time