Cable Modem Issues - T3 Timeout & Failed to acquire QAM/QPSK symbol timing, Uncorrectable Codeword Errors

I have xfinity gig extra plan. I have a Netgear Nighthawk CM3000 modem, which is brand new. I just replaced a relatively new CM2000 due to these issues, only to find the same thing happening with the new modem. The routers are TP link Decos, but they are fine.

I am having issues with intermittent connectivity, some random restarts, and web pages that don't load fully. There also seems to be some interference issues. I checked the modem logs and sure enough there are an enormous amount of uncorrectable codeword errors in my downstream OFDM channels only. They rack up at an alarming rate of almost one million per hour at times. I also have critical events for T3 timeouts, and SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing, whenever the modem is restarted. 

I want to note that I took the modem down to where the coax line comes in from the street, and attached it there to test it before any splitters, other cables, etc. The power levels went up, but the issues persisted. Thus I suspect the issue is either outside the house, or possibly the single coax line that comes from the outside of my house (ISP entry point) to inside my house. Likely the former.  I will post some diagnostic info below for reference. This was taken just minutes after rebooting. Again, despite power levels rising a bit, all of the issues remained the same when connecting the modem right to the first coax line. Same issues with two modems as well.

Does anyone know what the issue might be? Will I need a tech visit? If so, Xfinity please help!

Cable Diagnostic

Status: Good

Action:
Your setup looks fine. If you can't access the internet, make sure you properly activated the modem. If modem has been activated and you still can't access the internet, contact your service provider for troubleshooting help.
If you can access the internet but has other internet issue, the Netgear Cable Knowledge Base can provide additional troubleshooting info.

CM Status: Good

Downstream Status: Good

    Downstream Power Level: Good

    Downstream SNR Level: Good

Upstream Status: Good

    Upstream Power Level: Good

Current Time: Mon Sep 16 18:36:32 2024

Startup Procedure
Acquire Downstream Channel: 513000000 Hz  Locked
Connectivity State:          OK       Operational
Boot State:                  OK       Operational
Security:                   Enabled   BPI+
IP Provisioning Mode:       Honor MDD   IPv6 only

Downstream Bonded Channels
Channel LockedStatus Modulation ChannelID  Frequency     Power    SNR   Correctables Uncorrectables     
      1     Locked     QAM256     29     513000000 Hz     -5.3     40.1     0     0
      2     Locked     QAM256      9     387000000 Hz     -4.2     41     0     0
      3     Locked     QAM256     10     393000000 Hz     -4.2     40.9     0     0
      4     Locked     QAM256     11     399000000 Hz     -4.8     40.5     0     0
      5     Locked     QAM256     12     405000000 Hz     -4.6     40.5     0     0
      6     Locked     QAM256     13     411000000 Hz     -4.4     40.7     0     0
      7     Locked     QAM256     14     417000000 Hz     -4.4     40.8     0     0
      8     Locked     QAM256     15     423000000 Hz     -4.9     40.5     0     0
      9     Locked     QAM256     16     429000000 Hz     -4.6     40.7     0     0
     10     Locked     QAM256     17     435000000 Hz     -4.5     40.7     0     0
     11     Locked     QAM256     18     441000000 Hz     -4.9     40.4     0     0
     12     Locked     QAM256     19     447000000 Hz     -4.5     40.5     0     0
     13     Locked     QAM256     20     453000000 Hz     -4.6     40.5     0     0
     14     Locked     QAM256     21     459000000 Hz     -4.6     40.4     0     0
     15     Locked     QAM256     22     465000000 Hz     -4.9     40.2     0     0
     16     Locked     QAM256     23     471000000 Hz     -4.6     40.4     0     0
     17     Locked     QAM256     24     477000000 Hz     -4.9     40.2     0     0
     18     Locked     QAM256     25     483000000 Hz     -5.2     40     0     0
     19     Locked     QAM256     26     489000000 Hz     -5.3     40     0     0
     20     Locked     QAM256     27     495000000 Hz     -5.4     39.7     0     0
     21     Locked     QAM256     28     507000000 Hz     -5.6     39.9     0     0
     22     Locked     QAM256     30     519000000 Hz     -5.9     39.6     0     0
     23     Locked     QAM256     31     525000000 Hz     -5.5     39.8     0     0
     24     Locked     QAM256     32     531000000 Hz     -5.4     39.9     0     0
     25     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     26     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     27     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     28     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     29     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     30     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     31     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0
     32     Not Locked     Unknown      0     0 Hz     0.0     0.0     0     0

Upstream Bonded Channels
Channel   LockedStatus  ChannelType ChannelID   SymbolRate        Frequency       Power     
      1       Locked       ATDMA     47       5120 Ksym/sec       29200000 Hz       48.0 dBmV
      2       Locked       ATDMA     45       5120 Ksym/sec       16300000 Hz       48.8 dBmV
      3       Locked       ATDMA     46       5120 Ksym/sec       22800000 Hz       48.8 dBmV
      4       Locked       ATDMA     48       5120 Ksym/sec       35600000 Hz       47.0 dBmV
      5       Not Locked       Unknown      0       0       0       0.0
      6       Not Locked       Unknown      0       0       0       0.0
      7       Not Locked       Unknown      0       0       0       0.0
      8       Not Locked       Unknown      0       0       0       0.0

Downstream OFDM Channels
Channel   LockedStatus  ProfileID  ChannelID    Frequency       Power       SNR/MER    ActiveSubcarrier    Unerror    Correctable   Uncorrectable
      1     Locked     0 ,1 ,2 ,3      1     537000000 Hz     -5.42 dBmV     37.7 dB     1108 ~ 2987     28760832     25848155     458143
      2     Not Locked     0      0     0 Hz     0 dBmV     0 dB     0 ~ 4095     0     0     0

Upstream OFDMA Channels
Channel   LockedStatus    ProfileID    ChannelID    Frequency       Power
      1     Not Locked     0      0     0 Hz     0 dBmV
      2     Not Locked     0      0     0 Hz     0 dBmV

Event Log
         Time               Priority     Description
Mon Sep 16 18:25:23 2024     Notice (6)     CM-STATUS message sent. Event Type Code: 24; Chan ID: 1; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2.;
Mon Sep 16 18:23:25 2024     Notice (6)     CM-STATUS message sent. Event Type Code: 16; Chan ID: 1; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;
Mon Sep 16 18:21:20 2024     Notice (6)     CM-STATUS message sent. Event Type Code: 16; Chan ID: 1; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
Mon Sep 16 18:21:03 2024     Notice (6)     DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;
Mon Sep 16 18:20:59 2024     Notice (6)     TLV-11 - unrecognized OID;
Time Not Established     Notice (6)     Honoring MDD; IP provisioning mode = IPv6
Time Not Established     Critical (3)     No Ranging Response received - T3 time-out;
Time Not Established     Critical (3)     SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;; 

thanks!