@cargot_robbie I always cycle in a dress - not much longer than knee length has been typically unproblematic for me. I make sure I'm sat on it so the back doesn't flap around the wheel. I do have a rear rack and mudguards and it's never yet caught on anything whilst cycling.
I wear leggings or shorts underneath - the front will get caught in the wind. I think some people do manage to prevent that, but I wear leggings anyway so 🤷♀️