Verify Email - User Info Rate Limit

I am implementing an email verification flow in a mobile app. We prevent the user from creating an account in our app until their email is verified. For the UX, we wanted to poll the userinfo endpoint to determine when the email was verified (since this is an asynchronous event). I am concerned about the rate limits for the user info endpoint which brings up some questions:

What exactly are the rate limits for the user info endpoint?

Is there a best practice for this flow - main goal is to determine when the user has verified their email? (I did not see any web hooks that would have helped, and it seems like we need to fetch this information manually – but it seems like polling might not be good approach given the limits).