Shopify Flow Archived Items = 0 Quantity

{% assign v = product.variants | first %}

{{ v.inventoryItem.id }}

Regarding location_id, do you have 1 location or many? If just one, you could do:

{% assign location_inventory = v.inventoryItem.inventoryLevels | first %}

{{ location_inventory.location.id }}

Otherwise, you could go to the list of locations in the Admin (Settings / Location) and click on one. In the URL you will see an ID for that location.
31-47-p8oyi-x83fv.png

I think you need the format like this “gid://shopify/Location/35317088278” substituting your own ID