Nodejs and MongoDB consultant for FeathersJS/Express project -- 2

Hello, I'm developing a multiplayer mobile game using unity as a game client (in C#) and MongoDB + NodeJS + [login to view URL] as a server. Your objectives as a JS expert is to initiate me to a MEAN stack-like development and offer insights for the code architecture to reduce server <->client latency and server ressource needs. If you have experiences in server scalability operations and AWS products it's a plus. You have to be able to start ASAP. Thank you