Competitive shooter netcode

Design the authoritative netcode backend for a real-time competitive shooter with 64-player matches, a 64 Hz server tick, and a hard budget of <80 ms end-to-end input-to-render under typical 40 ms RTT. Players spread across regions; you must run thousands of concurrent match instances. Cover the transport, how the simulation stays authoritative, how clients hide latency, and how you keep cheaters from forging movement.