Can’t remove checkout fields

Attempting to use:

add_filter( 'woocommerce_enable_order_notes_field', '__return_false' );

It won’t remove the field.

I’ve also tried the one directly from the woocommerce checkout fields customization page:

// Hook in
add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );

// Our hooked in function - $fields is passed via the filter!
function custom_override_checkout_fields( $fields ) {
     unset($fields['order']['order_comments']);

     return $fields;
}

And that doesn’t work either. How do I add/change/remove fields with cartflows installed?