You can display dynamic information in your online store by adding sections or blocks that can connect dynamic sources. Shopify

All themes include a “Cart” feature that provides your visitors with visual feedback that they have added an item to

Shopify recently launched an integration with Google’s Pagespeed Insights tool for measuring online page speed performance. Optimizing your online store

To remove the cart icon in the header In the header editor, add this CSS to CUSTOM CSS in order

Shopify lets you associate one image with one variant, but what if you want to have multiple images associated with that

You can update the theme follow as Shopify guidelines. This link has detailed steps for you to upgrade the theme