Allow other roles to edit Notifications

You can overwrite the Notification post type capabilities. See the capabilities for specific roles.

In below example you are allowing everyone with Editor role or greater to manage the Notifications.

add_filter( 'notification/post_type/capabilities', function( $capabilities ) {
    return [
		'edit_post'          => 'publish_posts',
		'read_post'          => 'publish_posts',
		'delete_post'        => 'publish_posts',
		'edit_posts'         => 'publish_posts',
		'edit_others_posts'  => 'publish_posts',
		'delete_posts'       => 'publish_posts',
		'publish_posts'      => 'publish_posts',
		'read_private_posts' => 'publish_posts',
	];
} );

Please note that capability the user have to have is unfiltered_html. Otherwise the notification configuration won't be saved properly.