[rft]

About 2 years ago I had a similarly bad cable connection. I could push nearly 500mbit/s UDP through it, as advertised, but HTTPS downloads and TCP streams would only reach about 80mbit/s each. I could run multiple of them in parallel to max out the downstream on TCP alone. I also tracked it down to a low packet loss on the connection that caused TCP to reduce its rate.

I wondered whether you could add a VPN-like layer that retransmits and potentially reorders TCP packets itself without letting the actual endpoint TCP stack handle it. That way it should transparently remove the packet loss at the cost of additional complexity and higher latency.

I wish I knew about Hysteria, but I never made the connection to censored networks. It seems like it could be (ab)used for this use case.