What you're describing is a symptom of cable internet, and likely not of the servers. What I'm saying is not guaranteed, but this is likely the case. And unfortunately bandwidth sharing (and associated packet reordering/jitter) is a feature of the DOCSIS standards, so while your ISP can choose to add more bandwidth to your area, they are not required to for cable internet to still "work."
You should try running some speed tests and/or bufferbloat tests around the time you see issues, and show them to your ISP. Whether or not they can actually fix them is a different matter.