I’m using the authentication bot recommended by a forum member last time. This bot works on a referral system: invite four people to earn 1 credit, and 1 credit lets you authenticate once—that means you can get a year of Google AI Pro for free.
Once you have credits, send submit to the bot and provide your Google email + password + 2FA key. I recommend registering a new account for this. After you get Google AI Pro, update your password and 2FA key immediately.
The whole process is shown above: just send the required info in the given format, wait for the link, click it, add any card you want, and you’ll unlock Google AI Pro.