Exporting Pages don’t retain permalink structure

Good day. I recently launched a new website and exported several pages from the old website that has Custom Permalinks installed and active to the new website that has Custom Permalinks installed and active. I didn’t notice that the page slugs didn’t get exported with the pages and did months of work on them, launched the website and now have about 150 pages with wrong permalinks. How do I export the permalink structure created from Custom Permalinks from one site another? Honestly, I installed the plugin to just change the permalink structure for a few pages. I didn’t realize that even if I made a simple change to any page slug with the plugin active, it would not be changed in WordPress itself. That if I deactivated the plugin, all the normal page slug changes I made over the time the plugin was activated would disappear and all of my incoming links would break. Perhaps I’m missing something, however, it appears at the moment that my entire website now depends on Custom Permalinks to be active, otherwise all my page URLs will change back to the default page slug. Any advice or guidance on the above (potential) issues would be greatly appreciated. Thank you.