Internet has been problematic for months, still waiting on service technician

Those T3 errors are most likely caused by noise.  You need to contact support and have them check your line for ingress.  They can do this at the curb so no need to enter your house.  This could also be related to the DRW errors which correlates to power fluctuations, which again, can be caused by noise between you and the CMTS.  Noise can also be fed back from a neighbor screwing up the whole neighborhood.  More than likely its cabling between the street and your DMARC or the cabling/connections in your house/apartment.