Delta Lake always creates a new version of parquet files whenever any operation is performed. In order to have a better performance, you can Optimize the table which rewrites the parquet files for that table behind the scenes to improve the data layout (Read more about optimize here: https://learn.microsoft.com/en-us/azure/databricks/sql/language-manual/delta-optimize). It is a simple command: OPTIMIZE <Table Name>

Also, you can run the VACUUM command to clean up old versions of the data and free up storage space: https://learn.microsoft.com/en-us/azure/databricks/sql/language-manual/delta-vacuum