Moving to different folder will break a few paths that had been already in place which had been set by some plugins or theme. If your post editor is commercial or custom plugin like Elementor/PageBuilder,…, let’s try deactivate those plugins, and activate them one by one. Also switching theme to WP default theme and see if that helps at all. I would suggest to try all these on staging website, not live website.
I unpublished all plugins and went through the db before I moved site and changed all the urls. It’s post, pages and the customizer. I’m getting errors with the post.php file also. I changed to the 2019 theme and have the same issue. I also reloaded WP to the newest version.
Do you mind to share what exactly is the error with the post.php file? it’s because that’s a WP core file I’d like to understand more about it. thanks.
I’m not finding that error now but I’m seeing it maybe that gutenberg is not loading. All of the text editor parts/blocks are missing.