In 16 version of theme we added a lot of improvements to regular woocommerce pages. Here is also some tricks how to improve them even more
First of all, make sure that your Cart and Checkout pages have System page template. Go to Pages – all pages and find them. Edit pages and check right side area

Now, select special patterns in Gutenberg

We added there few ready title blocks, just drop them before cart and checkout shortcode. Now, you can edit titles in block. Also, make sure that there is correct link to your cart in these blocks