You can try to add the standard OTP even for Microsoft crap. If it asks you to register for mfa and opens the screen that says something about downloading the Microsoft authenticator app there is a small link at the bottom, letting you use another app. Then you get a qr code that you can scan with any other auth app.

I use a basic OTP password instead of Microsoft's ironically less secure (see SMS as 2FA) with my work MS account. Perhaps your org disabled it but it is definitely something a Microsoft account can do.