To assist you in the best possible manner, I kindly ask that you please provide me temporary wp-admin info (wp-admin URL, username, password) to the Private Content area, this will allow me to thoroughly investigate and address your concerns more efficiently.
You are using WooCommerce Blocks. You need to remove them completely – https://monosnap.com/file/DYynCYO5DELtMiDQW2E99Yhx3TFPCs. Then define the Shortcode element with [woocommerce_cart], save the page and as a result, the default template for Cart page will be shown. The same goes for the Checkout page.