I agree with Stephen, trying to buy something in anticipation that it might be needed is not the way to go.
Get what will cover your current requirements, and currently Broadcasting is at UHD, just barley starting, and full 4K is a ways off, except for cable streaming sites like NetFlix.
Since yipou are new to this type of camera, get a Fuji HA or one of the SD lenses like Stephen recommended. Yesterday’s top of the line lenses are better than today’s lower end 4K range. A good 4K B4 lens is going to cost you more than you are going to want to spend ($15-20K).
Cheers