How can I stop Odoo from auto-populating attribute values after I add an attribute to a product?

I am using a Manufacturer and a Brand attribute so that my customers can use this as a filter in the shop and also see the information on the product page. Display type is "Select", Variant Creation is "Never", and Filter Visibility is "Visible". All is good on the front end.

When I create a new product and add the Manufacturer attribute, all 200 possible values are auto-populated. I need to delete 199 of them... I would like the attribute value to be blank and select one option.