Ask HN: Am I being unreasonable saying no to Work MFA on personal phone?

I just got 1 day's notice that my SMS-based MFA to get into Work Email (Outlook) is being discontinued. The only option IT is providing is to use Microsoft Authenticator on personal phones.

For reasons that feel wholly irrelevant to the issue, I have decided I don't want to use my personal phone for anything work related. The last time this came up, I was made to feel like a nuisance, and eventually compromised, using my personal phone for SMS-based MFA.

Am I being unreasonable here? Should I just cave and adjust my personal patterns/workflows to make my personal phone available for work use like this?

Does your employer offer a cell phone stipend program? Many times, employers will pay to "use" a portion of your cell plan, basically allowing them to require apps like MFA on personal devices. (or require on call access to employees)

If I was made to go into the office each day it would be a hard no for me. But I'm willing to put up with this type of thing when working from home. But I have some caveats with that as well. If I'm made to work on company provided hardware then I'd say no to the personal phone for MFA, even if working from home. If they're setup to allow me to use my personal equipment for work then I'm willing to use my personal phone for MFA.