Is there any way to automate filling the "harmonized system code" field without "Managed Markets"?

We have many many products in our EU site (Spain) that have blank harmonized system code fields. We can not use “Managed Markets”.

Is there any possible way to automate this?

I tried doing a Matrixify download, updated the field, uploaded and it made even more of the harmonized system code fields blank.

Yes it can be automated. If many products have blank Harmonized System code fields, we can update them in bulk using a properly formatted import file or through the API. Sometimes matrixify blanks fields if the column name or format doesn’t exactly match Shopify’s expected structure.

One option is to export the products again, update only the HS code column carefully, and re-import while keeping the rest of the date unchanged. Another approach is to run a small script or automation that fills the missing HS codes based on product type or category.