Summarizing from the discussion (above). @Nelson, Thanks for sharing the info/solution with the community.
Issue: How to see the amount of daily storage used in Azure Application Insights
Solution: Azure Support advised to run the below query in log analytics, to help find the total daily usage split by what data type was taking up most of the space:
Usage
| extend BillingTelemetryType = DataType
| extend BillingTelemetrySizeInMB = QuantityUnit
| extend BillingTelemetrySizeInMB = Quantity
| summarize sum(Quantity) by bin(TimeGenerated,1d), DataType
| render columnchart
Since the Microsoft Q&A community has a policy that the question author cannot accept their own answer. They can only accept answers by others, I' have summarized and posted the solution/answer to benefit the community users to find the answers quickly.