Website magento 2.3.4. issues

Hi, I have a website in Magento 2.3.4. The website has more stores and each store have their store view in 3 different languages. The product page for this website was customized as following: 1. the Gallery (the first part of the product page, product photo and short description) was customized. It was created a function in product page backend that when is active, in frontend product page appears customized, when is not active, in frontend product page is default. 2. the rest of the product page, bottom part, the same principle, just that this function as applied on all the website without having the possibility in backend to choose the new layout or not. I have some issue to fix, some of them regarding this customization we did for the product page that gives an error after we did an update for the template and some of them regarding the Porto theme we used. Very important: ⇒ delivery time date 2 days starting from when I provide access credentials to backend and cPanel of the test server + 1 day to check and solve possible problems (if not providing the project in the established time our team will not pay for this project). ⇒ all the changes will be done on a test server (copy of the production website) and will be described in our file + the files that were modified, so we can reproduce all changes on online website. There will be absolutely no possibility to make changes directly on the online site. See attached the issues list and some screenshots for some of them.