Fix for broken Elementor landing pages when using custom permalinks (v3.4.3+)

functions.php

/**
 * Fixes landing page 404 when non-standard permalinks are enabled.
 *
 * @param \WP_Query $query
 */
function elementor_pre_get_posts( \WP_Query $query ) {
	if (
		// If the post type includes the Elementor landing page CPT.
		class_exists( '\Elementor\Modules\LandingPages\Module' )
		&& is_array( $query->get( 'post_type' ) )
		&& in_array( \Elementor\Modules\LandingPages\Module::CPT, $query->get( 'post_type' ), true )
		// If custom permalinks are enabled.
		&& '' !== get_option( 'permalink_structure' )
		// If the query is for a front-end page.
		&& ( ! is_admin() || wp_doing_ajax() )
		&& $query->is_main_query()
		// If the query is for a page.
		&& isset( $query->query['page'] )
		// If the query is not for a static home/blog page.
		&& ! is_home()
		// If the page name has been set and is not for a path.
		&& ! empty( $query->query['pagename'] )
		&& false === strpos( $query->query['pagename'], '/' )
		// If the name has not already been set.
		&& empty( $query->query['name'] ) ) {
		$query->set( 'name', $query->query['pagename'] );
	}
}
add_action( 'pre_get_posts', 'elementor_pre_get_posts', 100 );

Not sure if anyone else is still having this issue but I got the following to work:

Step 1 - return to standard URL structure

Step 2 - add the following to functions.php - this is for /blog/ to be added before posts only - based on this post: https://wordpress.stackexchange.com/questions/300806/custom-permalink-for-post-only-not-custom-post-types

// Elementor Landing Page Custom URL Structure Fix

/**

• Add new rewrite rule
  /
  function create_new_url_querystring() {
  add_rewrite_rule(
  'blog/([^/])$',
  'index.php?name=$matches[1]',
  'top'
  );
  add_rewrite_tag('%recipes%','([^/]*)');
  }
  add_action('init', 'create_new_url_querystring', 999 );

/**

• Modify post link
• This will print /blog/post-name instead of /post-name
  */
  function append_query_string( $url, $post, $leavename ) {
  if ( $post->post_type == 'post' ) {
  $url = home_url( user_trailingslashit( "blog/$post->post_name" ) );
  }
  return $url;
  }
  add_filter( 'post_link', 'append_query_string', 10, 3 );

/**

• Redirect all posts to new url
• If you get error 'Too many redirects' or 'Redirect loop', then delete everything below
  */
  function redirect_old_urls() {
  if ( is_singular('post') ) {
  global $post;
  if ( strpos( $_SERVER['REQUEST_URI'], '/blog/') === false) {
  wp_redirect( home_url( user_trailingslashit( "blog/$post->post_name" ) ), 301 );
  exit();
  }
  }
  }
  add_filter( 'template_redirect', 'redirect_old_urls' );