Lumineers could def headline rather than third billing! If you look at their monthly Spotify streams (22m) compared to most if not all of the other suggestions here they’re a way bigger act.
Christ, a second Trump term with control of the House and the Senate, PLUS two Supreme Court Justices ripe for retirement who’s replacements would be chosen by Trump meaning four of the eight for the next 30 or so years would be his ultra conservative picks. Terrifying stuff.
I'd also mention Ypsigrock, a nice boutique indie festival in Sicily in early August, C2C in Autumn in Turin (mainly electronic), Spring Attitude in Rome in September.
But they're all small festivals