Internet Issues

I have ATT Cable Internet as it is the only option in my rural area.

Every night around 8:15 my internet cuts out and is intermittent for the rest of the night. I have had multiple ATT techs come out and replace the lines inside the home, lines on the poles, and replace the modem & router. They eventually told me there is a surge in the line, possibly from the nearby streetlight kicking on. I had Entergy come out and check it was properly ground and run a power surge test and they reported to me no issues.

Any ideas before I call out another tech and continue this mess of possible finger pointing.