Packet Loss in the Evening (7PM-2AM)

I have been experiencing intermittent packet loss (particularly at night) over the last few months with associated event log errors on my cable modem (MB8600). Screenshots are attached.

PingPlotter capture over Ethernet:

Update 2020-09-03 — Packet loss starts at ~19:00 EDT, or start of "internet rush hour", 19:00PM - 23:00PM.