So…they wanted him to take a polygraph interview regarding the nature of his relationship with Peter Strzok, and he resigned instead, did I understand that correctly?
Polys are also subjective. They keep asking the same questions over and over again until there's some indication they can point to and say you're lying. It might be a sneeze, cough, or a deep breath at the wrong time. It's also generally a multi hour to multi day ordeal. I wouldn't bother if I was them.