How to Hide a Button on Add Record Page in Freedom UI?

I am working in Freedom UI and need to hide a custom button on the Add Record page.

The requirement is:

• The button should be hidden when creating a new record
• The button should be visible after the record is saved (Edit mode)

I tried using a business rule with the condition:
Page is opened or one of the attributes in conditions changed.

And checked whether a specific field is filled in. However, I would like to confirm the best and recommended approach to detect Add mode properly in Freedom UI.

Is checking whether the Id field is filled in the correct way to handle this scenario?
Or is there a better way to control button visibility based on Add/Edit mode?