Thank you for posting you on Microsoft Q&A, from above description I could understand you want to add increase the number of technical profiles and get telemetric data at each step during a journey when a technical profile is called.
Please do correct me if this is not the ask by responding in the comments section.
There are no specific logs, graph query or tools to analyze the technical profile impact on a custom policy however the error and performance logs could be validated via Application insights.
To collect B2C technical profile error messages and performance metrics, you can use Azure Application Insights. Azure Application Insights is a service that allows you to monitor the performance and usage of your applications, including B2C technical profiles.
- For usage analysis follow Track user behavior in Azure AD B2C by using Application Insights
- To collect telemetric data you may follow: Collect Azure Active Directory B2C logs with Application Insights
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Thanks, Akshay Kaushik