@JFarmer
Initially used ArcGIS Enterprise Builder 10.8.1 for base deployment, later upgraded the deployment using ArcGIS Enterprise Builder 10.9.
Both ArcGIS Workflow Manager Server and ArcGIS Workflow Manager Web App were installed on the same machine that of base deployment.
ArcGIS Enterprise Builder federated ArcGIS Server using web adaptor only, please refer to the below screenshot.
Enabled server roles are:
Note: ArcGIS Pro installed on a separate machine, it got access to "Service URL", but no access to "Administration URL" of above screenshot.