ウィザード形式で値が保存されない

お世話になっております。
現在ウィザード形式で新規登録のサーバーサイドの実装をしております。

問題なく遷移し、完了ページまで行けるのですが、情報がなにも保存されません。
binding.pryをすると、入力された値は取得できます。

知識不足で初歩的なミスかもしれませんが、お力を貸していただければと思います。
user.rb (バリデーションはまだ途中です)

class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable
  
  validates :nickname, presence: true, length: {maximum: 20}
  validates :email, presence: true
  validates :password, presence: true, length: {minimum: 7}
  validates :password_confirmation, presence: true, length: {minimum: 7}
  validates :family_name, :first_name, presence: true
  validates :family_name_kana, :first_name_kana, presence: true
  validates :birth_year, :birth_month, :birth_day, presence: true


  has_one :shipping_info, dependent: :destroy
end

shipping_info (バリデーションはまだ途中です)

class ShippingInfo < ApplicationRecord
  belongs_to :user, optional: true

  validates :family_name, :first_name, :postcode, :prefecture, :city, :house_number, presence: true
  validates :family_name_kana, :first_name_kana,  presence: true
end

registration_controller.rb

# frozen_string_literal: true

class Users::RegistrationsController < Devise::RegistrationsController
  # before_action :configure_sign_up_params, only: [:create]
  # before_action :configure_account_update_params, only: [:update]

  # GET /resource/sign_up
  # def new
  #   super
  # end

    # POST /resource

  def new 
    @user = User.new
  end

  def create
    @user = User.new(sign_up_params)
    unless @user.valid? 
      flash.now[:alert] = @user.errors.full_messages 
      render :new and return
    end
    session["devise.regist_data"] = {user: @user.attributes}
    
    session["devise.regist_data"][:user]["password"] = params[:user][:password] 
    @address = @user.build_shipping_info
    render :new_address 
  end

  def create_address
    @user = User.new(session["devise.regist_data"]["user"])
    @address = ShippingInfo.new(shipping_info_params)
    unless @address.valid? 
      flash.now[:alert] = @address.errors.full_messages
      render :new_address and return
    end
    @user.build_shipping_info(@address.attributes)
    @user.save
    session["devise.regist_data"]["user"].clear
    sign_in(:user, @user)

  end

  # GET /resource/edit
  # def edit
  #   super
  # end

  # PUT /resource
  # def update
  #   super
  # end

  # DELETE /resource
  # def destroy
  #   super
  # end

  # GET /resource/cancel
  # Forces the session data which is usually expired after sign
  # in to be expired now. This is useful if the user wants to
  # cancel oauth signing in/up in the middle of the process,
  # removing all OAuth session data.
  # def cancel
  #   super
  # end

  # protected

  # If you have extra params to permit, append them to the sanitizer.
  # def configure_sign_up_params
  #   devise_parameter_sanitizer.permit(:sign_up, keys: [:attribute])
  # end

  # If you have extra params to permit, append them to the sanitizer.
  # def configure_account_update_params
  #   devise_parameter_sanitizer.permit(:account_update, keys: [:attribute])
  # end

  # The path used after sign up.
  # def after_sign_up_path_for(resource)
  #   super(resource)
  # end

  # The path used after sign up for inactive accounts.
  # def after_inactive_sign_up_path_for(resource)
  #   super(resource)
  # end
  protected

  def shipping_info_params
    params.require(:shipping_info).permit(:family_name, :first_name, :family_name_kana, :first_name_kana, :postcode, :prefecture, :city, :house_number, :building, :home_call_num)
  end
end

よろしくお願い致します。