Match CSV columns data sitting at S3 with Redshift table column data
One way to do this can be like

Create a glue catalog (No cost)
Create external table using redshift query editor (Still no cost and no need to run crawler as well)
Now you have the data as a table.
Compare both the table one in your redshift cluster and another one is extenal table.

The only cost that will be incurred is of scanning the data while running query which is equal to 5$ per TB.
I'm still new to AWS ecosystem and doing a POC on certain components of aws. I have to match CSVs data with Redshift table data - col to col match. Can anybody direct me to point where I can get an idea how to execute above. Thanks in advance.