„In order to change the default media upload location, you need to edit the wp-config.php file located in the root directory of your WordPress installation. If you want upload directory to be wp-content/files then you will need to place the following code in wp-config.php
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define( ‚UPLOADS‘, ‚wp-content/‘.’files‘ );
If you want the upload directory to be outside wp-content, like http://www.example.com/files/ then you need to set upload path in wp-config.php like this:
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define( ‚UPLOADS‘, “.’files‘ );
Remember you can still choose whether or not you want uploaded files to be organized in month/year folders in Settings » Media.“
from: https://www.wpbeginner.com/wp-tutorials/how-to-change-the-default-media-upload-location-in-wordpress-3-5/