First Social Login: avoid setting IdP e-mail address as username automatically by default

In a “First Social Login” (e.g.: Google) flow in Keycloak, is there a way to avoid setting username automatically to IdP’s e-mail address by default, while setting the other data (e-mail address, first name, last name) normally? Instead, I would like to show an “update profile” page with username field blank and the other fields pre-filled with data retrieved from IdP.

I want this because, in my application, my username must be an identity number, which doesn’t match e-mail address pattern.