iPhone with Microsoft Authenticator on it stolen. How do i remove the authenticator privilages from this device?

Question

Hi,

My iPhone was recently stolen, and it had the Microsoft Authenticator app linked to several of my Outlook accounts.

I still have full access to my account, and I’m trying to deactivate the authenticator on the stolen device to prevent the thieves from using it for login. Under my "Security" dashboard, in the "Ways to prove who you are" section, I see an active option for "Enter a code from an authenticator app," but it doesn't specify which device this is referring to. This has left me wondering, how I'm supposed to make the authenticator on the stolen phone obsolete.

So, my questions are:

1. How can I deactivate the Microsoft Authenticator app on a device I no longer have?
2. If I deactivate the "Enter a code from an authenticator app" option in the "Ways to prove who you are" section and then reactivate it on my new device, will the stolen device also be reactivated and usable as an authentication method again?
3. Is there a way I can see the devices that currently has an active Microsoft Authenticator app linked to my account? Can there be more than one at any given time?

This has left me really frustrated and I've used a lot of time on it. I would really appreciate your help.
Thank you very much.

Best Regards,
Emil