Hi DamodarD,
My name is Didi, an Independent Advisor. I'll be glad to help you today.
You may try searching the audit log for SharePoint files to track who downloaded a particular file.
https://techcommunity.microsoft.com/t5/microsof...
Search the audit log:
https://docs.microsoft.com/en-us/microsoft-365/...
I hope this helps.
Best regards,
Didi