Hi There,
You may add this code on your pro child theme functions.php file:
/**
* Enable unfiltered_html capability for Normal Administrator.
*
* @param array $caps The user's capabilities.
* @param string $cap Capability name.
* @param int $user_id The user ID.
* @return array $caps The user's capabilities, with 'unfiltered_html' potentially added.
*/
function km_add_unfiltered_html_capability_to_normaladmin( $caps, $cap, $user_id ) {
if ( 'unfiltered_html' === $cap && user_can( $user_id, 'administrator' ) ) {
$caps = array( 'unfiltered_html' );
}
return $caps;
}
add_filter( 'map_meta_cap', 'km_add_unfiltered_html_capability_to_normaladmin', 1, 3 );
I have tested it on your site and it works. It is a variation of the code presented here. I just edited the role for it to work on normal admin. Feel free to add the code again if you want. Please just note as stated on the link, it is not available by default due to potential security vulnerabilities.
Hope this helps.