Remove metabox field with filter

I'm trying to create a filter so we can remove fields from a metabox.

This is the function that I have created to it. It returns null as aspected, but the field is still there in the metabox.

Code:

    /**
     * filter fields
     */
    public function syb_filter_fields( $fields ) {

        foreach ( $fields as $field ) { 
            
            if ( $field['id'] == 'boat-details' ) {
                
                foreach ($field['fields'] as $key => $value) {
                    
                    if ( $value["id"] == 'field-id' ) {

                        $value = NULL;
                    
                    }  
                }
            }
        }
 
        return $fields;

    }