Every website I've encountered so far offering TOTP 2FA (aka. "Google Authenticator") gives the user the ability to display the used secret to generate the QR code in text form, which can be easily copied for some generators that don't have the ability to scan a QR code.

Unfortunately it seems that the used secret is being stored in the server side user session because there is also no way to extract the used token from the image URL, it's just /account/two_factor/qrcode/.