Your Nine to Five account and progress are tied to your Steam or Stadia account, and it is therefore possible to only have one account per player on each platform. Moving progress or purchases from one Steam account to another is not possible. To create a new game, you shall create a fresh Steam or Stadia account.
It is possible to link your Steam and Stadia accounts, more details you can find here: Account linking - Steam and Google Stadia
If you want to delete your account or request your account information as according to GDPR, please reach out to our support team via this form: link