Assuming you're referring to the backend side of things for online/multiplayer games, working through the Hathora tutorials in the docs can be a good first introduction to general idioms related to backend systems architecture: https://docs.hathora.dev/#/builder/

From my past consulting experience though, the distributed systems side of games is all over the place. Designs tend to need to be customized for each games needs, which usually directly influences which technologies are chosen.