Speed Issues after upgrading to Next-Gen Symmetrical Internet Plan + XB10

Hey all, hoping someone from the team (or anyone who's hit this) can help. For years, I have had the 2-gig plan with an XB8 modem. Recently, my neighborhood got next-gen symmetrical speeds, and I switched to the XB10 modem, but I started running into speed issues right away.

Here's a breakdown of events:

• Before: Ran an XB8 for years, got a steady ~2Gbps down and 300–360Mbps up, no matter the time of day.
• After upgrading to XB10: Uploads were great (1.5–2.1Gbps), but downloads got flaky, fine in the morning, then dropping to 750–800Mbps during evening peak hours. Swapped back to the XB8 to test, and the same download drop happened, so it wasn't the modem.
• After the line fix: Had three tech visits, then a field crew replaced the underground drop line (took about 5 minutes). Right after that, things got worse, not better: downloads are still bad, and now uploads are hard-capped at around 490 Mbps too.

Checking my signal stats at 10.0.0.1, Upstream Channel 43 shows Modulation as OFDMA, but the Channel Type is stuck on TDMA, basically the old legacy fallback mode. That would explain the 490Mbps upload ceiling. My guess is the quick line swap left something behind (a bad splice, an old filter/splitter at the pedestal) that's blocking the next-gen frequencies.

At this point, I've already done the modem swaps and had multiple truck rolls, so another standard tech visit or factory reset won't fix it. This looks like it needs someone who can pull the RF signal history on my node and send a plant/line tech back to the pedestal.

Has anyone else run into upload/download issues after moving to next-gen symmetrical with an XB10? Curious if this is a wider node issue or just my line.