Thank you for posting this in Microsoft Q&A.
The exact definition of disable and delete varies based on the target app's implementation, but generally a disable indicates that the user can't sign in. A delete indicates that the user has been removed completely from the application.
whether the integration is able to soft delete an account with this configuration and eventually hard delete after 30 days.
With the current configuration, the integration will not be able to soft delete an account. Soft delete is a feature that allows you to recover deleted objects within a certain time frame, typically 30 days. If the "Delete" action is not enabled in the user provisioning configuration, the integration will not be able to delete user accounts, either permanently or temporarily.
If you want to disable accounts while employees are on leave, you can use the "Update" action to change the user's account status to "disabled" or "inactive". This will prevent the user from logging in to their account, but their account will still exist in Entra ID. When the employee returns from leave, you can use the "Update" action again to change the user's account status back to "active".
For more information referring this documentation: https://learn.microsoft.com/en-us/entra/identity/app-provisioning/how-provisioning-works#deprovisioning
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.