We highly recommend downloading Authy for two-factor authentication (2FA) on your Gemini account to avoid any inherent security faults presented by SMS.
To download, search "Authy" in your mobile device's app store and select to download the Authy app. Ensure that when you create an account, you use the same phone number registered with Gemini. Once the download is complete, open the app and you will see a Gemini token loaded - there will be no need to scan a QR code. Next, we highly suggest disabling the multi-device option to safeguard your Authy account one step further.
If you have any additional questions about 2FA or the security of your account, please reach out to us at firstname.lastname@example.org.