Hi,
The system-generated tables you are seeing are for storing Classic metrics. This is the backend storage for generating the charts you see in the portal for your storage account. They are being retired on August 31, 2023.
You may adjust settings such as what items are tracked, how many days before deleting data, etc., by navigating to the storage account -- Diagnostic settings (classic) blade. Article below describes this in more detail:
Please see article below for details on transitioning to Azure Monitor and key differences:
Transition to metrics in Azure Monitor
https://learn.microsoft.com/en-us/azure/storage/common/storage-metrics-migration
Please click Accept Answer if the above was useful.
Thanks.
-TP