Great question — answering as the UphillTech team:
The new Shopify functions feature that handles automatic/code discounts is designed to trigger upon cart changes. As a result, the discounted amount is intended to be visible exclusively on the cart and checkout pages. This behavior is by design, and currently, there is no built-in way to directly display the discounted amount on other pages using this feature.
Full answer by Lakshay Kalra: https://stackoverflow.stackexchange.com/a/76983213 (CC BY-SA 4.0).
Need it done for your business? UphillTech.