Blurry image on single product pages

Hi

My issue is on individual/single product pages. The images appear slightly blurry until I engage the zoom hover over. How can I improve this? Here is an example: https://naturalethicsfr.wpcomstaging.com/produit/balle-en-chanvre/

The issue appears on Safari and Firefox, but not in Chrome, Edge

I have tried clear the cache.

I tried larger images with up to 300dpi, as well as, 96dpi, and 72dpi and they all appear blurry although while looking at them in the media library (edit image) they are full size and entirely clear. It’s almost as if there is a conflicting setting that is reducing the quality.

Thanks you for your help

The page I need help with: [log in to see the link]