Cox never had the infrastructure for gigablast to begin with. When I first moved into my neighborhood, gigablast was not even a thing. A year later, without touching a single thing on the CTMS/node in which my neighborhood feeds into, magically gigablast becomes an option. I am at a constant 18% packet loss and line jitter average of 80 or more during all day time hours. Download speeds are not the most impacted thing your experiencing right now, check your packet loss and jitter, that is far worse issue then only get a 450mb download speed.
I am only getting around 90 mbs on a 150 mbs package and all the issues above I just stated. However, if I call cox sales right now and ask to be upgraded to gigablast, they would sell that garbage to me in an instant. Id still be at 90 mbs download speed, would just be paying more for it each month. Right now with how poor of a shape Cox infrastructure is in with the work from home situation we are all in, you honestly dont need to pay for more then a 50mbs package.