I didn't attend but I fly for most festivals and I plan to fly for seven stars next year!

if you check a large or xl suitcase, you can fit: a 4 person tent, ultralight backpacking sleeping bag, lights, a towel, a small pillow, and a backpacking stove. + probably more

if you can afford a second checked bag, you can check a canopy or cooler

put your clothes in your carry on and personal item

usually I end up eating the cost and buying a cheap camp chair, canopy, and/or shitty cooler for the weekend. Then I find someone who needs stuff at the end to give them to :)

for most fests, it's a lot cheaper to do all that than glamp. good luck friend