Intermittent latency spikes — confirmed distribution line issue, two tickets, no resolution

I've been fighting persistent intermittent latency spikes since moving into my home (new construction, Comcast-only development) and I'm hoping to reach the Digital Care Team, because front-line support and field techs have not been able to resolve this.

The problem: constant intermittent ping spikes (jitter to 300ms+) on a wired connection, with zero correlation to bandwidth — my plan tests at full speed (1200+ Mbps). It's latency/jitter, not throughput. It makes online gaming unplayable (rubber-banding, delayed inputs) and the spikes happen with my upstream completely idle and no other devices using the connection.

What I've already ruled out (extensively):

• Replaced the gateway (XB-series) — problem persisted
• Wired Cat6, tested direct to the gateway with no splitters — still spikes
• Local network is clean: pings to my own gateway (10.0.0.1) are 0ms/0% loss during active spikes, while pings to the second hop (Comcast's first router) spike to 300ms+. The fault appears immediately upstream of my gateway.
• Downstream signal/SNR all in spec; bufferbloat tests clean when idle
• Modem has shown T3 timeouts on the upstream

This points squarely at upstream noise ingress / return-path impairment — which I understand can't be read from my modem and needs the CMTS polled from your side.

Why I'm escalating here: A field technician already confirmed this is a known issue with the outside distribution line in my area requiring a maintenance crew. Despite that:

• Ticket [Edited: "Personal Information"] was marked "resolved" with no work performed — no crew came.
• Special request ticket [Edited: "Personal Information"] has been repeatedly rescheduled every time I contact support, with no work ever done.
• The technician who told me to follow up never responded.

One more thing: the coaxial tap/pedestal box in front of my house is sitting open and exposed to the weather. Given that water intrusion / corrosion in the line is a known cause of exactly this kind of upstream impairment, I suspect this may be contributing.

Could the Digital Care Team please poll the CMTS to check my node and upstream health (Rx power, SNR, error/timeout history), confirm the status of the open maintenance work, and get the distribution-line repair actually completed? I have ping logs, traceroutes, and a photo of the open box available. Thank you.