@bascule polyglot smuggling?
5 years ago I made a honeypot TCP server supporting ssh, http, https and Minecraft at the same time, that decides which protocol to use from first few header bytes. So it was kinda reverse polyglot.
I think some HTTP proxies do scan the CONNECT streams for structured data, so they might suffer from "false synchronization" just like frame transmissions in telecommunications.
@link Self-hosted dedicated server on OVH. They have very good anti-ddos.
You can make a trick with 3 servers, with separate geolocations that proxy to the main server.
Cheaper - VPS is also an option (with antiddos too)