You are using custom Add to cart button, not Buy button of the them that is why it is not open cart drawer
Topic summary
Add to cart button redirects to the cart page even though the theme setting is configured to open the cart drawer (a side panel showing cart contents). A screen recording and product link were provided to illustrate the issue.
One suggestion was to verify settings: Online Store > Themes > Customize > Theme settings > Cart > Drawer. The setting is already selected, but the behavior persists.
A likely cause identified: the store is using a custom Add to cart button instead of the theme’s native Buy/Add button, so the theme’s JavaScript that opens the cart drawer isn’t triggered.
Another participant suggested following a solution from a Shopify Community thread (via an app-based approach) to stop redirects to the cart page.
The store owner located the button’s code but isn’t sure how to modify it to open the drawer; no code details were shared. No confirmed fix yet.
Status: Unresolved. Next steps implied by the discussion include switching to the theme’s default button or updating the custom button to trigger the drawer (or using the referenced app-based method).