Migration of built in groups

We are doing cross forest migration using QMM for AD. I have a concern related to the bullt in groups “domain admins” and “domain users”  that we are not migrating and making sure that the users who were in those groups in the source and once they are migrated they don’t lose access to the resources. We won’t be migrating those groups to the target. . What is the best tool to use to analyze permissions? How do you usually re-assign permissions in the target for those built in groups? What is the simplest and best approach here to ensure the access to resources after the migration.