For a round face I suggest that middle length with bangs will be the most gorgeous option. A lot of celebrities are now combining flattering  layers and medium length hair. But you have to make sure that your face is actually round, bu still there are different hairstyles for face shapes https://lovehairstyles.com/hairstyles-for-face-shapes/ here and you can choose your perfect hairstyle after going through that catalogue. I would say that straight bangs more likely to suit diamond shaped face, but for roung, more layers and thick bangs would go great.

What type of hairstyle is best for a round face?