For those who want to deal with non-standard OIDC profiles, the solutions seems to fetch the user in the Auth0 DB (which is created with all the non-standard fields) since you have the Auth0 user ID in the OIDC response and do what you need in your action flow script.
BTW this implies to implement your own data mapping for each OIDC connections if there is no coherence in the users fields the IDP send you.