Hi Ariel,
Unfortunately a DB link is required for the Data Warehouse and the job to perform properly.
You can let your DBAs know that this is a mandatory requirement and that the link is only between DWH and PPM database in order to perform select statements from PPM when the Load Data Warehouse job is executing.
Alternatively, you may try removing the link and adding it once per month before the Load Data Warehouse job is running. However this is a customization that is not recommended and may lead to issues. Load Data Warehouse Access rights also uses the dblink so in case you add new users and want to run the job it will fail, etc. This is not a tested approach so you will also have to test it thoroughly.
The best way to go here is to create the link as per the Install Guide and work with the DBAs to ensure it’s done in the closest possible way to your best practices.
Hope this helps -Nika