Once again, there are multiple OOB Indicators available to you for Incident Resolved aspects. See screenshot
Benchmarks are PA, but if you don't use that feature then see:
I do not understand why you won't review those. Also, there is the "Performance Analytics Content for Incident Management" plugin, that can be activated in your instance if you don't have the four above. Review the related document on PA. What you want should be available OOB.
What you're asking for is easy I believe, but I don't have data to test. If one of the above is not what you want then create an Indicator Source for the metric_instance table, Indicator for Definition "Create to Resolve Duration", and Data Collector Job. You will need to review some related training or documentation. I don't think any of us can do the work for you.
