I think Big Thief will either open the main stage or play in the tent and Yard Act will definitely play in the tent. If you're lucky they'll play the same time as Raye so then you can catch Skrillex and Fred at the main stage after
There was music playing in the background. If I remember correctly they played the Burnt Norton interlude while she was down there taking selfies with the fans.
At this point it's just a matter of personal taste if you prefer Stormzy and Fred again or Massive attack and LCD. None of them are much bigger than the others
Tbh looking back at it the 20th and 25th anniversary lineups were not much bigger than those of the years before or after them. So it's always just been a marketing tool.