unable to update custom attributes to product using rest API

I have created the custom attribute through rest API and it is also reflected in magento admin, after which when I tried to update the product with the attribute code.it won’t worked.

Below is my JSON for creating attribute code

 $data = [
                           "attribute" => [
                                 "is_wysiwyg_enabled" => false,
                                 "is_html_allowed_on_front" => false,
                                 "used_for_sort_by" => false,
                                 "is_filterable"=> true,
                                 "is_filterable_in_search"=> true,
                                 "is_used_in_grid"=> true,
                                 "is_visible_in_grid"=> false,
                                 "is_filterable_in_grid"=> true,
                                 "position"=> 0,
                                 "apply_to"=> [],
                                 "is_searchable"=> "1",
                                 "is_visible_in_advanced_search"=> "1",
                                 "is_comparable"=> "1",
                                 "is_used_for_promo_rules"=> "0",
                                 "is_visible_on_front"=> "1",
                                 "used_in_product_listing"=> "1",
                                 "is_visible"=> true,
                                 "scope"=> "global",
                                 "frontend_input"=> "text",
                                 "entity_type_id"=> "4",
                                 "is_required"=> false,
                                 "is_user_defined"=> true,
                                 "default_frontend_label"=> $attribute,
                                 "frontend_labels"=> $attribute,
                                 "backend_type"=> "varchar",
                                 "default_value"=> "",
                                 "is_unique"=> "0",
                                //  'attribute_set' => 'Default', // Specify the attribute set code
                                //  'attribute_group' => 'General',    
                             ]
                         ];

This is for product updating for custom attribute

$data = [
                      "product" => [
                        "sku"=> $productsku,
                       // "attribute_set_id"=> 4,
                        //"attribute_set_id" => $mage_attr_set_id,
                       // "entity_type_id" => $entity_type_id,
                        "visibility" => 2,
                        // "custom_attributes" => $subArray
                        "custom_attributes" => [
                            [
                            "attribute_code" => "selling_unit_of_measure",
                            "value" => "each"
                            
                            ] 
                      ]
                      ]
                    ];