Thank you for reaching out.
Based on my understanding of your question above,
Are you trying to compare the differences between the configuration of these managed rules for the WAFs? If yes you can run this REST API call which will retrieve the WAF policy with specified name within a resource group. The API call will list the disabled Managed rules for the WAF, custom rules set-up and exclusions.
OR
If you just wish to compare Managed rules like DRS 2.1, OWASP 3.2 etc. These rules are listed here
Thanks