I've added some products from printful, managed to change the width of the 'personalize design' button but this change has caused the text of the button to be in 2 rows. Can't seem to find a way to put it in one row.
incase your theme code same class or style used for the same for all over theme then it will affect on complete website.
I see the home page and product page button different.
if you want to same them copy the style and add to another button style.
you can find the option under the theme customization button style, if need help with custom code I can do that. you have to give me dev access to your store.