It’s impossible to totally eliminate the risk of a cyberattack. No reputable cybersecurity company could give that assurance. For the same reason, you cannot simply pass or fail a TIBER test.
In fact, it would pose a higher risk to state you’d passed as you might take no further action.
Complacency in cybersecurity is risky.
Protecting your organisation from cyberattacks should be continual. And it must be specific to your risk profile and particular operations. As attacks become more sophisticated, so must your testing to keep one step ahead.