Hello! I've run into the same issue, but as I want run my server on Colyseus Arena I can't define handlers directly before server. According to https://docs.colyseus.io/arena/getting-started/modify-colyseus-server/ I need to use arena.config.ts. Where, by design, I can manipulate expres app only after the server is created

Is there any way to add POST to allowed methods with this configuration? Or may be it is better to move to self-hosted option?