Sorry, but your request/the desired result is not fully clear to me, but I will try to answer.
If you want to edit WC pages using Elementor Pro, contact support of this Pro plugin to get assistance, there should not be restrictions from our theme side for this, at the same time, we can’t guide you, because it is a separate plugin.
You can disable our Single Product Builder via Theme Options, without any unintended consequences for the rest of the site.
Within next 2 days, we will release an update that contains fix and improvements in the work of our Advanced layout for Cart/Checkout pages, by that time, it would be better do not use it. You can configure other things on site meanwhile. Also, the delight of “Thank you” page will be like – https://prnt.sc/GtHDoJTv2Iyu with the new layout activated.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.