@Laura2592 I don't keep outdoor areas immaculate, by any means. There could be leaves, cat hair on the cushions, whatever. I rake up the small yard where the trees are and tidy things up and clean that cat hair before a guest arrives, if I have time, but I certainly don't keep cleaning it during a guest stay. I home-share, so I think guests are more accepting in that situation, and I've never had a guest complain.
I wouldn't concern myself with your guest's complaint at all. If outside insect life and fallen leaves is an issue for guests, what in the world are they doing booking a countryside place?
Maybe just provide a small wisk broom and some rags near the outdoor seating area and point it out to guests when they arrive, to deal with the "inevitable daily leaf and dust accumulation" on outside furniture.