I´m searching for a solution to put a text on the same height as the size variant which is also clickable to make a popup out of it for a size chart.
All these size charts apps slowing down the theme to much
It can be done without using the app but requires custom work. It will not affect the speed of your store. You can contact Shopify Experts here https://experts.shopify.com/
or I can do this task for you.
Thank You!