Natural Fiber Under-Dress Slips?

Looking for a good natural fiber slip to wear under my short summer dresses that need an extra layer to make them properly opaque so nobody sees my undies.

Any specific brand recommendations that use cotton/merino/actual silk (NOT polyester)? I am ok with blends but I want it to be at least 60% natural fiber so that it’s breathable. So far I’m only finding basically plastic clothes for this category. Prefer to spend less than $50 if possible, but willing to go up to $80 if it’s truly well made.