Add div on EMED Tag

you can use ’embed_oembed_html’ to wrap that iframe inside the div.

add_filter('embed_oembed_html', 'Oembed_youtube_no_title', 99, 4);

function Oembed_youtube_no_title($html, $url, $attr, $post_id) {
  return '<div class="embed-container">' . $html . '</div>';
}

Didn’t test please let me know if it works for you.