Blank "Customize" menu after Flothemes migration to Kadence

I'm in the process of switching from Flothemes to Kadence, and after much trial and error, I've found that I'm having problems accessing the Customize menu under Appearance (when I switch to the Kadence theme. The "Customize" page appeared blank: no menu options, no display of my website to view changes) and no fix was found, not even disabling all plugins, not using the Health Check plugin in maintenance mode, not switching to another version of PHP, not finding any problem in my browser's console or logs, so I decided it might be a problem. found any problems, so I decided that a fresh install of WordPress might be in order.

I know the Kadence theme is working fine.

So, I want to do a fresh install, but there are a lot of pages, blog posts, SEO metadata and images I want to save. Images aren't too much of a problem, I can download them one by one without too much of a problem. But I am very concerned about my pages, blog posts and SEO metadata on each page/post. Is there any way to export all this information and import it into a fresh WordPress installation?