Hello,

1) The button is coming through a script code. The size of the button is typically controlled from the chat system website from where you made its settings.

2) I saw the screenshot you attached. To change the breadcrumbs to shop base you need to Go to Settings >> Permalinks >> Product Permalinks.

Set them according to your needs.

Screenshot for Clarification: https://ibb.co/jGPLLXW

Best Regards.