Shopify API PII REST error

Since the deprication of leagacy custom apps in the admin environment of a merchant with the start of the new year, we run into issues that we did not experience while testing of the new wow.
We already had a lot of chats with Shopify support, but they could not help us and advised to post here.

Situation:
We want to create an app that allows us access to the merchants store so we can download the order information via the Admin REST API for fulfilment and customer service. All seemed to work fine, when we tested the setup in our dev portal, but when we had the client (merchant) create an app in their dev dashboard, they have no way of requesting PII permissions for it. For us this shows up as an option in the partner portal, but the merchants do not have a client portal. So we can not get access to the clients orders.

What we tried:

  • have client create app in their dev dashboard → no access to request PII permission for this merchant in this way

  • create app per client in our dev dashboard and provide the distribution link for installation → PII permissions do not show up for this app on our partner environment

we need the following permissions:

  • read_assigned_fulfillment_orders - write_assigned_fulfillment_orders - read_customers - read_discounts - read_draft_orders - read_fulfillments - read_gift_cards - write_inventory - read_inventory - read_merchant_managed_fulfillment_orders - write_merchant_managed_fulfillment_orders - write_order_edits - read_order_edits - read_orders - write_orders - read_products - read_returns - read_shipping - write_shipping - read_third_party_fulfillment_orders - write_third_party_fulfillment_orders

Is there anybody here who could solve this?

All clients are on the Growth plan or above, so they should have access to PII via API