The solution is not in blueprint. Or rather I would strongly suggest not doing it in blueprint.
You need a often called match making system. Or more specifically a matchmaking server.
A static thing on the internet the game can connect to where new servers register and players can request a server to join. That separate server will then look through the list of currently available servers and forward the player to the best option.
It’s not usually something done within the engine itself since it provides a quite massive overhead of stuff to load up while in reality you would want a lightweight server so it’s cheaper to run.
Cheers