WordPress.org site editor showing a broken version of my site (while site viewer is mostly fine)

Today my site lost a lot of its functionality. I can’t press the “view page” buttons while in the editor, the “edit site” shortcut in the dashboard doesn’t work and I can only edit the site with the “edit site” button on the top left while viewing the site. What’s really weird is the home page looks fine on the viewer, but when I try clicking the buttons to get to other pages it says “the requested URL was not found on this server”.
I also can’t do a lot of other things in the editor. The style is gone from the background, it can’t find the other pages for the header (says Page List: cannot retrieve pages) and the header also says “Site Title Placeholder” instead of my actual site title. Basically something is going super wrong with the editor where it’s missing like 75% of what should be on my site.
The actual viewing part of my site seems mostly fine except for the missing page connections.
Any ideas of what could be causing this?? The only thing I’ve changed recently was pasting from the backup folder in xampp/mysql/backup into xampp/mysql/data/ since that’s the fix for MySQL failing to run in xampp. I don’t think that should actually change anything with the site though since the backup folder doesn’t have the folder with the site database, only sql stuff.

Edit: I also found out that whenever I try to update a page after making a change, I get the error “Updating failed. The response is not a valid JSON response.”

 

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