I have a seperate line coming from the box outside the house (that is connected to the street pole), this line comes into the room with a 2 output splitter (TV & modem). Last year a tech installed a signal amp to increase the levels to all devices using coax. All connections are tight and no damage to the cables.
The information below is from a owned TP-Link Archer CR500
Error page 1
Errors page 2
Errors page 3
The signal stats are good. The log entries, not so much. Perhaps there is noise ingress into the line(s) somewhere.
The bottom line is, are you actually experiencing any connection quality and / or speed problems, or are you just focusing on the error log entries ?