New password/ password reset widget on native app instead of browser

Our signup flow looks has two screens, one to capture email and another one to capture password after the email is verified.
We are trying out with trial version, where the email screen opens in the native app but the password window opens up in the browser after the user clicks on the verification link. This gives a bad user experience to switch between native and browser windows.

With the licensed version, we will be creating custom domains.
I have checked other threads where custom domain is referred. Can you please detail out how the redirection will restrict the user to only stay on the native screens for all the flows?