Wordpress - Media files exist in upload folder but not showing up

Just by uploading files into the wp-content/uploads won't show up in the Media Library , those media ID's needs to be there in the database to show up in the Media Library.

If you already have files in the uploads folder and want to add them into the database, you can use this plugin to add files from server.

But this is not the correct solution instead fix the permissions issue for that uploads folder.

You can use Media Sync for new updated plugin for the year 2020. The plugin description reads

You can scan all files that are in “uploads” directory and see which ones are actually in Media Library and which ones are just sitting there. Then you can select those that you want to import to database and therefore make them available in Media Library.