Hi, sorry but let me say this, if you want implement good services and strong back end, we need implement many technologies and microservices, we need implement Nosql database, real time publish subscribe system like to kafka, streaming server like to spark and more....
This all is to make a client and Server-API consumible by the client like to Steam. An Server-API to allow streaming, messages, and more.
I can develop this but no the games (i know people to develop games).