The idea is that clients connect to a login server to a map called “start_map” and then retrieve player data like “characters” and its inventory from the database, which is managed by a node.js server. Each server (login server and world servers) shall be setup as dedicates servers.
Once the player has selected its character, the client will then travel with that character to a game world server (the server to connect to depends of whether its a new character or if the character has logged out on a world previously).
To connect to a game world server, the client uses ClientTravel and with it along, the character data such as inventory items, etc.
Characters are not persistent. They will be destroyed along with the starter map. Only controllers are persistent.
Besides you don’t need a starter map to handle any of that. The game mode and game state can handle all of it.
The only limit to the number of players you have on any map is going to be based on the hardware of the server and the performance of the game on clients.
You definitely need to hit the docs.