Very Slow Upload Speeds / Limitation of ISP wiring?

Hello! So I've just updated to a DOCSIS 3.1 modem and my download speeds have increased to the advertised rate on my plan (500+ Mbps) and I am very satisfied on that front.

However, my upload speed hasn't budged from what it was on the previous DOCSIS 3.0 modem (10-12 Mbps.) Even when skipping my router and wiring directly into the modem itself. My plan is 500/500.

I understand that the plan specified UP to 500 upload, not a guaranteed 500, but I thought at the very least after switching from DOCSIS 3.0 to 3.1, and after seeing an increase in my download speed, I'd at least see my upload increase a bit. Is it possible that the wiring to my residence isn't up to the task?