I live next door to a hacker…what cable box do you offer with the highest security protocols

The hacker next door is able to hack my hdmi cord and who knows what else? I upgraded my hdmi cord to a fiber optic shielded cord and he is still able to hack into my cable connection. The cable box  is XG2v2 P. The hacker has advance miltary grade hacking tools. On Monday I am upgrading my gateway to wifi 7.  I turned off my WiFi in late March.  I have a 4k tv that is part of a home theater system that I have disabled along with my lg tv. Any suggestions would be much appreciated. I will be testing Xfinity’s new security shield since I am still contemplating what firewall to purchase..I am leaning towards a firewalla since I am a none techie at 69 years old.