.world is fine for the most part, a lot of us are just trying to keep things more distributed amongst smaller instances so that not any one instance can overly dominate with many large comms.
It helps keep things healthier overall for the Threadiverse
I'm not super familiar with OBS for... actually capturing/streaming games, but if you add a new source of "Game Capture", select your game window and the check the "Capture Audio" option it should work. Though I see it is marked as beta lol