You print the MFA QR code, and give it to an executive that locks it up in a safe or offsite storage.
In a past life, we printed the MFA QR code and the head of finance put it into a safe.
In a past life, we printed the MFA QR code and the head of finance put it into a safe.
We even have these amazing things that securely share passwords or other secret data between multiple authorized users.
Seriously just scan the QR code and put it in any password manager that supports TOTP and it will start outputing codes.
And we are talking about the root account for your production AWS account. No need to get fancy. Just print the QR code, and put it in a safe hoping you never need it.