BlackBerry UEM (12.6+) supports custom App Policies in BlackBerry Dynamics applications.  One item that is likely confusing things here is that App Policy was renamed to App Configuration in BlackBerry UEM.

To create a new configuration setting:

1. Select the app in the app list on BlackBerry UEM
2. Click on the + button highlighted in the screenshot below.
3. Give the App Configuration an name, choose values and click Save.

An admin can have multiple App Configurations.  When assigning the application to a user or user group, the administrator can select the App Configuration that will be deployed.