If you have a superb ventilation the soil doesn’t have to absorb the moisture of the poop. The poo gets dry within a several hours. Then you can use soil just as well as sand.
I would skip the plastic. Make a construction with a solid poop board and higher roosts. Chickens like to roost higher than the nest box area.
I use cardboard from wine boxes

, a little sand + dried greens from the garden on the poop board. Add more greens, shavings or hay from the nest boxes a few times to cover the poo

. The cardboard makes it easy to take it all out at once right into the wheelbarrow. But there are many other choices you can make. Let it depend on you’re personal preferences, you’re climate and chicken behaviour.