Hi Kevin - there are a couple options when it comes to accounts that can’t be correlated. For some high level info on cleaning up and managing uncorrelated accounts, I’d suggest reading this Compass article.
Specifically around certifications, you can create an exclusion rule to make sure that you aren’t including the uncorrelated accounts in the review. For access requests, there are other options available, such as for a given quicklink, in the configuration (‘Global Settings’->‘Quicklink Populations’) where you can specify who any given population can make requests for using a ‘custom criteria’ and here filter on identities that are correlated.