Always associate the process data entity of Employee, customer, … using a 1-1 association to System.Account.
Because the account is the passport of the user to authenticate itself when accessing the application. The moment you start inheriting, the process data = the passport and thus in ALL usages of the process object, the account(User)/Passport data is carried with it. In short; you don't want this related to a secure app.
Back to the original question:
- Create a single entity with all attributes matching the excel columns
- Create an employee entity with 1-1 association to System.Account
- Create an import microflow, which imports all data from excel to this import entity
- Create a second microflow which maps the imported data from import entity to Employee & account
- Don't forget to set the association between the employee and account!
- After mapping delete the list of import entity
- This microflow can be a sub-microflow in the same microflow as the Import, so that there isn't a second user action required