How do I turn 2 years of source data into a snapshot table

I have 2 years of source data that I want to turn into a scd2 but it seems that I have to run dbt build for each file in dbt that I have to iterate through all the files.

If I run snapshot on all the files at once it returns dbt_valid_to null for the millions of records that I have.

Is there a way to run dbt snapshot in all my files at once or code that I can use to iterate through all of them?