If you want to check whether your account has a unique player ID and whether it is linked to your account via Google, Apple, or Facebook, you can check the following:
1. Press the [More] button on the menu at the bottom of the screen.
2. Click the [Account] item on the More menu.
3. You can check whether PID information, Facebook, Google, and App Store are linked in the account item.
※ Once you have linked your Facebook and Google Play accounts, you will be able to retrieve the accounts associated with those accounts when you connect to the same Facebook / Google account again, even if they are disconnected by pressing the associated button.