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You can start by enabling logging to gain more robust details around the operations happening on the account such as Request URI, Client IP, User Agent Header etc. which shall help you back tracking to the source.
The user agent shall help pointing the calls are from which source such as ADF, DataBricks, some other SDKS etc. This along with request URL shall reviewing your workloads writing to the particular containers and you can then work with your developers further for optimization ahead accordingly.
Below are the links to start with:
https://learn.microsoft.com/en-us/azure/storage/blobs/monitor-blob-storage?tabs=azure-portal
https://learn.microsoft.com/en-us/azure/storage/blobs/blob-storage-monitoring-scenarios
For more further discussion you can raise a support ticket further with either billing or storage team (for technical details)
Kindly let me know if you have any further queries. I’m happy to assist you further. Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.