welcome aboard.
WordPress uses Media Elements JS for default video/audio player. You can disable this scripts with this code. Please add this code to your theme’s functions.php
function deregister_media_elements(){
wp_deregister_script('wp-mediaelement');
wp_deregister_style('wp-mediaelement');
}
add_action('wp_enqueue_scripts','deregister_media_elements');
PS. This code de-register mediaelements.js from all WordPress (with your current theme).