Is there a way to upload External Forecast other than via FBDI which is a .xlsm template

Summary:

Is there a way to upload External Forecast other than via FBDI which is a .xlsm template

Content (required):

We are using only Supply Planning and Customer is not happy with the process to upload External Forecast via the FBDI (.xlsm template) process. The process is quite frequent in terms of new forecast creation and updates. They are finding this process to be cumbersome and without much control.

With the alternate approach as well, they need provision to capture the forecast related attributes like Item, Demand Class, org, Qty and Demand Due date which can assist with supply planning and forecast consumption. I am looking at the following options