The Apple Developer Program License Agreement and the Paid Apps Agreement are separate. Accepting the program license doesn't activate the Paid Apps Agreement. Apple requires the Account Holder to accept Paid Apps before offering In-App Purchases, and Apple's StoreKit sandbox setup also lists an active Paid Apps Agreement as a requirement.
In App Store Connect, open Business → Agreements and check the status of both rows. If Paid Apps is available, complete the agreement there, then check whether Apple requests tax or banking details. If the row is missing or the warning remains after acceptance, this looks like an account-side issue for Apple Developer Support to investigate. Send them your team ID and screenshots of the agreement status privately; don't post account or case details here.
For the empty product list, also verify that the product IDs in the app exactly match the IDs in App Store Connect and that the products have their required metadata, pricing, and availability configured. Apple’s sandbox guide has the setup checklist: https://developer.apple.com/documentation/storekit/testing-in-app-purchases-with-sandbox
Agreement help: https://developer.apple.com/help/app-store-connect/manage-agreements/sign-and-update-agreements/
Topic:
Developer Tools & Services
SubTopic:
Apple Developer Program