I was following the same tutorial to familiarize myself with the apps and try to enter content on the order confirmation page, but I can’t see it.
Making some changes to the code I can see a block in the other checkout steps, but not in the order confirmation page. I tried inserting logs and again, I see them in the previous steps, but not in the final one.
For the extensions not showing up on the Order Status page, was the placement-reference=ORDER_SUMMARY1 query param appended to the URL?
The default placement reference for dynamic extensions is INFORMATION1 which is not shown on the Order Status Page. More about the placement-reference query param can be found here.