CKEditor 5 was added to core in 9.3. This is going to be the new WYSIWYG editor in D10 and CKEditor 4 is being removed. Because CKEditor 5 was a ground-up rewrite all plugins must also be rewritten.
However, the Resize CKeditor plugin currently doesn't appear to have an upgrade plan. Based on documentation from CKEditor 5 the attributes this plugin makes use of (resize_dir, resize_enabled, resize_maxHeight, resize_maxWidth, resize_minHeight, resize_minWidth) are no longer needed.
No longer needed. The editor automatically grows with content. You can also limit its height with min-height and max-height or set it with height if you need. If you want to allow the users to manually resize the editor, you need to implement this by behavior by yourself.
See notes from CKEditor 5's options compatibility table
Determine next steps / future of this module and functionality as it pertains to CKEditor 5.
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Moreover ck5 has a common way to resize https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-wid...
I think this module will be used for Drupal 10 portals using Creditor 4 and will not used for Ckeditor 5 any more.
@andypost ckeditor5 may have a way to resize, but Drupal's CKEditor5 module doesn't. I have CKE5 installed, and I can't figure out how to get a resizable editor.