Simple game server with authorization and lobby

We need to make a small game server for a prototype of an online game. The server must accept connections from clients, provide simple authorization using a login and password, store accounts in the database, create lobbies and gather players into rooms. After the room starts, the server sends current match data (positions, points and simple events) to all participants, receives commands from the client and distributes updates to others.

Requirements: work via TCP or WebSocket, limit on the number of connections (for example, up to 100), logging connections and errors, basic protection against spam requests, config via file. We need instructions on how to run it on a clean Linux server, plus sources in the repository. There is no need to create a client part, but it is advisable to add a simple test client or script to check the connection and message exchange.

It is important that the code is understandable and without unnecessary complexity, so that the functionality can be expanded later.