Good morning!
You are correct that you cannot delete a property outright and that it must be archived instead. All archived properties will delete themselves after a 90 day period.
To archive a property, you’ll want to make a DELETE request to the following endpoint:
“/crm/v3/properties/{objectType}/{propertyName}”
In your case, you would replace the variable"objectType" with either “ticket” or “0-5” (as both will represent the Ticket object in the CRM), and “propertyName” would be replaced with the internal name value for the property you are attempting to archive.
Hope that helps!