Lots of codeword errors and disconnects - Time Warner Internet

This question is about "Lots of codeword errors and disconnects", with Time Warner Cable internet and apps. This has been an on-going issue for a while now -

I live in an apartment with the only thing attached to the coax coming into the unit being the cable modem. No TV box or splitters.

Three techs have been out so far, each time they've replaced something outside, and each time it's gotten a little better, but unfortunately has never been corrected. Signal levels were way out of wack initially, but seem to be within nominal levels now. Codeword errors accumulate gradually throughout the day, but the problem seems to be at its worst starting in the early evening, maybe 4pm to 7pm. Sometimes earlier, 10am seems to be the other hot time for issues. Codeword errors will ramp up, then the modem resets itself or disconnects for a short time.

Speeds are also less than they ought to be - I should have 300mbps down speeds, but seldom see more than 70mpbs, both on speed tests and 'real' downloading. Ping times are usually not too bad, but during the error streaks things will become rather laggy.

Image is about 4 days of up time.

I don't think there's much I can do on my end, but maybe there's something I can tell the next tech that shows up based on suggestions from here?

Lots of codeword errors and disconnects?