loading audio files from external sources?

i do not know if there is an easier way – but if you like to install a plugin – you have the oportunity to have external links added to media library:
https://wordpress.org/plugins/external-files-in-media-library/

Unfortunately mp3 is not included by default in the supported mime types. – But you can add it by a hook in child-theme functions.php:

add_filter( 'eml_supported_mime_types', function( $list ) {
	$list['audio/mpeg'] = array(
	'label' => 'MP3 Audio',
	'ext' => 'mp3'
	);
	return $list;
});

after that you can go to the settingspage of that plugin and activate all files that you like to add externally to your media-library.
Now you can add external links to media library via:

but be careful : those files could be erased without your knowledge. Or changed.

PS: on audio Element you can now add them like the selfhosted ones – but on playlist there is no total time for them
it is shown in the control panel – but not in the list: