Grass is terrible to dance on! It sucks all the momentum out of you. These dances were never danced on grass but on the streets whether paved or packed earth. Most of the dancing to this day is still done on the streets and you either have to put up with the surface available or not do it. At festivals stages are usually provided and these days are of quite good quality although likely to bounce a bit much and what suits a molly or cotswold team may not suit a step or rapper team. At one (large and well-established) festival in Belgium I badly cut my ankle when my foot went through the plank stage and stuck so we moved to the grass. The next year we were put on a full-sized professional stage.
In the end you can always use Sorbothane insoles.