Line Issues

I had recently purchased a netgear CM3000 because my old SB8600  was having some issues randomly one night with staying connected.  I had a similar issue years earlier due to my speed being higher than the modem was rated for.   Checked on My Account and sure enough, I had 2.1 and realized it was probably a capacity issue.  Went and purchased the CM3000, activated it via the Xfinity app, and everything was great for about a month.  Called in because I was having issues with the uplink light flashing.  Did all the normal troubleshooting and got a call from Tier 2 support.   Went through more troubleshooting and was told to get an RMA on the modem after hooking up the SB8600 and everything started working.   Well, this Monday the SB8600 starts having the uplink light blink and I lose internet.   Did all the troubleshooting and have a tech coming, but want to make sure I'm right in thinking I have a larger issue.

What I've found:

• Upstream power is 50+ dBmV
• About every minute I see this in the log:
  

  Critical (3)     No Ranging Response received - T3 time-out;CM-MAC=;CM-QOS=1.1;CM-VER=3.1;

• Have over 1 million uncorrectables
• Only 28 of 32 downstream channels are locking
• Downstream power is from -8 to -5 dbmV
• Going to the internet plugged into the router, every page comes up unsecured and won't proceed
• If I change the DNS on my router to Cloudflare 1.1.1.1 and Google 8.8.4.4 I can get to the internet but things are super slow.
• I have two aerial connections coming from a pole to my house and then they go underground to where my connection goes into my house that my modem is connected to

I appreciate any insight and assistance.

Respectfully,
Jeremy