You upstream power level is pretty high. High enough to cause upstream issues.
things that you can try.
remove any splitter, attenuators, amplifiers from your line. check for damaged cable, loose connectors, bad connectors, kinked lines.
Move the modem/router to right where the coax enters the home to rule out anything within the walls causing issues.
If still having issues, cox needs to check the line. ISP's fight not to do this and will regularly blame it on 3rd party equipment saying "its your modem, not our line". But your levels are high and you've only got 1 locked channel.
