To make custom settings for teams,
In Island Settings Use Dynamic Teams and set the number of teams to be the total number of different teams in your game.
To set up custom gameplay, remove all Win Condition related stuff from Island Settings, then you can use devices or verse to create the gameplay
For example setting up a tracker to count eliminations, then using an end game device to end the round or game when the tracker counts to a certain number.
Lots of devices, lots of gameplay options.
I’m not sure if UEFN allows us to load seperate servers for a game, unless via a Matchmaking Portal.
But you can load different areas of the same map depending on the players choices and have them teleport or spawn there.