Update Customer’s Custom Attribute after is successfully placed

I created a customer attribute called “new_customer” with a value of 1 YES.

Once an order is successfully placed by the customer, I want update the customer’s custom_attribute “new_customer” to 0(NO)

{
"id": 28,
"group_id": 1,
"created_at": "2021-07-21 18:39:00",
"updated_at": "2021-07-21 19:16:44",
"created_in": "Default Store View",
"email": "jane@gmail.com",
"firstname": "NewMitchell2",
"lastname": "NewThompson22",
"gender": 0,
"store_id": 1,
"website_id": 1,
"addresses": [],
"disable_auto_group_change": 0,
"extension_attributes": {
    "company_attributes": {
        "customer_id": 28,
        "company_id": 0
    },
    "is_subscribed": false
},
"custom_attributes": [
    {
        "attribute_code": "company_reg",
        "value": "Jane Cffsdfo222"
    },
    {
        "attribute_code": "has_purchased",
        "value": "0"
    },
    {
        "attribute_code": "new_customer",
        "value": "1"
    },
    {
        "attribute_code": "override_importer_of_record",
        "value": "default"
    }
]

}