So YouTubeTV just rolled out something called MultiView. It is for sports only and lets you watch 4 games at once, each game being 25% of your screen in a four corner layout. You can move to each window and get sound from that. You can select one of the windows and it will turn to that game. Looks pretty cool so far.
One drawback as far as I can tell. You don't get to pick the games you watch. It just showed up in my home screen as an option, I clicked it and the four games came up. That kind of sucks.