Internet keeps dropping out and coming back. Customer service won't help.

So for the past two months now our internet started dropping out randomly for a few minutes at a time. Tried calling Xfinity support only to be told "Everything looks good on their end" and that was about it.

Some info that may answer some questions ahead of time:

-The connection from their ground wire to my router is probably about 20ft.

-There are no splitters, It is a direct connection to the router with the exception of a wall outlet acting as a coupler.

-Router is a Netgear Nighthawk CAX80.

What I have done so far:

-Checked all connectors for corrosion/ bad terminations, everything seemed good.

-Made sure all connections were tight.

-Replaced the coax cable going from the wall outlet to the router.

Not really sure what else to do. I am a technician and have worked with coax before, but it was not for home networks. The router event logs are full of CM-STATUS event codes 16 and 24 bouncing back and forth, sometimes event codes 8 and 7, Dynamic Range Window violations, 'RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW', and T3 time-outs.

Thank you in advance to anyone who has some input.