Internet partially goes out every morning.

Problem:

Each morning right around the same time (not exactly the same time, but within a 1-2 hour window), the internet partially goes out.  By partially, what I mean is that any existing feeds, such as a Zoom meeting or a Twitch stream, continue to work, but all new connections, such as opening a new tab and navigating to google.com, will not work.  This occurs on every device, both wired and wireless.

What I've tried to fix:

1. Power cycling the modem always fixes the issue, but only for the current day / next ~24 hours until the issue reoccurs.
2. Comcast Tech Support re-provisions modem, which again, only temporarily fixes the issue.
3. Swapped out the modem with newer/better. Same problem occurs.
4. Multiple Comcast Service Techs come onsite.  They check the lines (look good).  They always have a different solution.  Solutions have included:
   1. MOCA filters
   2. Amplifier / signal booster
   3. New splitter
   4. New connections for every line
5. Changed DNS to use Google (8.8.8.8 & 8.8.4.4)

Additional Details:

• My current modem is an Arris SBG6700-AC.
• Here are the connection details both while the internet is only partially working and while it is fully working. https://imgur.com/a/QDeBySq
  • The main difference is the corrected/uncorrectables for channel ID 11
  • Per Arris documentation, the upstream power levels are out of spec.  They show either 39.0 or 39.5, whereas the specs state that they should be within 45.0 - 51.0.  However I do not believe this is the problem for two reasons:
    • The power levels are the same in both images (meaning unchanged when the internet is fully working)
    • My understanding is that low power levels correspond to less noise, and that the modem doesn't have to 'work' as hard to send/receive the packets.
• Historical event log does show some T3 timeouts, but those are at least 5+ days prior to when this issue started occurring.

Looking for guidance on what information I need to collect so that I can finally identify the root cause & correct.