Please let me know if you need access to my website.
And if I activate “Only show children of the current category” there is no link to go back to the main category list, we only have ” return to the previous page link” that is located outside of the sidebar.
This is the default widget of WooCommerce plugin and we can do nothing with its behavior because it depends on WooCommerce plugin code. You can contact WooCommerce support if you want to improve something with this https://wordpress.org/support/plugin/woocommerce/
Or submit additional customization request here to develop the individual widget that will suit all your needs. Oe look for third-party plugin that may offer you a widget as you need.
Our theme does not have special widget for the categories, we use the default one only.