High Amount of Uncorrectable Errors in my Home Wifi

I’m experiencing intermittent packet loss and major lag spikes on a wired Ethernet connection. The issue affects online games and Discord calls.

An Xfinity technician already came out and replaced my XB8 gateway, but the issue is still happening with the replacement gateway.

During the lag spikes, my local gateway at 10.0.0.1 continues responding normally, while external addresses such as 1.1.1.1 and 8.8.8.8 time out at the same time.

On the replacement gateway, downstream Channel 25 is showing approximately -11 dBmV power and 35 dB SNR, while the other downstream channels are around -4 to -5 dBmV and 40+ dB SNR. Channel 25 is also accumulating hundreds of millions of correctable and uncorrectable codewords while the other channels remain nearly clean.

Since replacing the gateway did not resolve the issue, could someone please investigate the coax line, connectors, drop, tap, or upstream signal/network for intermittent packet loss?