Does the SQL Transaction Log clear at the end of a loop?

I’m running SQL Server 2019 Enterprise Edition. Every month, we run a stored procedure that loads millions of records with service dates going back five years. I have 400GB of space allocated across 4 data files, and 100GB of space allocated for the Log file. The job frequently fails because the Log file fills due to Active Transaction. The database is in the simple recovery model. So, I believe it should clear at the end of each transaction. The developer changed the job so that it loops through and loads the records one year at a time.