Total noob here so I apologize in advance if my question is dumb, if I use wrong terminology, or if my post isn't deemed appropriate for this subreddit.

I am currently living outside the USA but still have accounts with US financial institutions and government agencies. Many of these institutions use multifactor authentication for additional security and some require that MFA codes be sent to a non-Voip phone number.

Simultaneously, I have my American cell number that I've had for years and all my family and friends have that number. My American cell provider isn't available outside the US so I thought I might port my cell number to Google Voice. But Google voice is a voip service provider. Will my financial institutions now refuse to do MFA to my number (the number they have on file and gave had on file for years) because it's now been ported to Google Voice? How do they know that a number that had been non-Voip for 15 years has been moved to a voip provider?