Hi,

Option 1: Export and import

Export all product variants with fields: external id, product_tmpl_id/name, attribute_value_ids, and name.

In Excel/Sheets, rebuild the Name by concatenating Template Name + Variant Attributes.

Import back into Odoo, mapping byexternal id

Option 2: Server action

Settings > Technical > Actions > Server Actions.

Model: Product Variant (product.product)

Action To Do: Execute Python Code

Code:

for product in records:

    new_name = product._get_combination_name()

    if new_name:

        product.name = new_name

Hope it helps.