Thanks a lot for clarifying your requirement. Since you need a combination of those attributes to match I think you will need the rule.
I think the rule you’ve posted above should work. I know the documentation doesn’t suggest returning identity object or name but i think it works in IIQ and should work in IDN as well.
I found this code snippet in one of the sailpoint documentations. https://community.sailpoint.com/t5/IdentityNow-Articles/IdentityNow-Rule-Guide-Correlation-Rule/ta-p/73693
//Note if searching for a user using IDN Rule Util logic, you will get a sailpoint.rule.Identity;
//You can use the following
sailpoint.rule.Identity foundIdentity = ....;
Map retMap = new HashMap();
retMap.put("name", foundIdentity.getName());
You can try using sailpoint.rule.identity class if it helps. You’ll have to modify the get calls accordingly.