Cumulative Layout Shift

Hi,

On this page of my site:
👉 https://www.scrapbooknine.fr/les-pop-up-pour-des-cartes-ludiques/

The Meow Gallery doesn’t display immediately on page load. This causes a layout shift (high CLS) because no space seems to be reserved before the gallery appears.

Is there a way to make it load earlier or reserve space in advance (via CSS or any setting)?
Goal: avoid the shift and improve Core Web Vitals score.

Thanks a lot for your help!

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