This dress is sold out in black, but you could always dye it with fabric dye.

Some sizes sold out, but again you could get this one in a different color in your size and dye it.

If you are willing to stray from cotton, this rayon dress with side slits seems to fit what you are looking for.

These are 65% cotton but not really flowy at the bottom:

https://www.fashionnova.com/products/mulberry-street-maxi-dress-black

https://www.forever21.com/us/shop/catalog/product/f21/dress_maxi/2000319861

Hope this gives you some ideas!