@Magi-Cut Developer Apologies for the delayed response, to review trusted signing account platform metrics, resource logs, and activity, currently we have these options which are defined here - https://learn.microsoft.com/en-us/azure/trusted-signing/how-to-sign-history coming to your ask related to cost associated with it you can refer to this https://azure.microsoft.com/en-in/pricing/details/storage/blobs/ which helps to estimate the pricing for the storage account.
Let me know if you have any further questions, feel free to post back.