Client credentials oauth flow from partner app not working

Authentication & Access
2

I just read this topic: Installing custom app - #8 by Tiwa_Ojo . If I understand correctly, client credentials authentication only works in these scenarios:

  1. A Partner Organization app authenticating to a dev store in that same Partner Organization.
  2. An merchant owned app authenticating to a production store owned by that same merchant.

And, specifically, this scenario is not supported for client credentials authentication:

  1. A Partner Organization app authenticating to a production store not owned by that partner.

Is this true? If so, what are the recommended authentication options? My application has no Shopify UI at all. All I want to do is just download some order data from a server that we manage that is written in java using the Shopify API.

Thanks again!