We've had some push back from staff regarding the installation of the Microsoft Authenticator as they feel that the Microsoft Authenticator app will spy on them or provide IT staff with access to their personal information.

I would have a hard time calling them narcissists. They're not that important for IT to orchestrate that entire project just to spy on a few employees... What a joke.

I'm looking for some examples of how you dealt with and resolved similar situations in your own organizations.

Where I've worked they've either had to do it or get a job elsewhere. There's legitimately no reason not to install a MFA app. This is a management/HR issue; not yours.