Remove thumbnails (featured images) from all posts in WordPress with PHP

/**
 * Removes thumbnails (featured images) from all posts.
 *
 * @see https://wpcodebook.com/wordpress-delete-thumbnails-all-posts-programmatically/
 * @see https://developer.wordpress.org/reference/classes/wp_query/
 * @see https://developer.wordpress.org/reference/functions/delete_post_thumbnail/
 */

$query = new WP_Query( array(
	'fields'         => 'ids',
	'posts_per_page' => -1,
	'post_status'    => 'any',
) );

if ( $query->have_posts() ) {
	foreach ( $query->posts as $post_id ) {
		delete_post_thumbnail( $post_id );
	}
}