Instead of Deployment Server, I'll prefer Cluster Master to handle HEC configuration and tokens on all Splunk Indexers in Cluster (As far as I remember only pain point is when you'll push bundle from CM to Indexers for new HEC token(s), it will restart Splunk process on Indexers)
Thanks for your inputs. I didn't think about this solution. The point about restart Splunk process is the same with Deployment-Server. But it makes more sense now to me to leverage the Cluster Manager than the Deployment-Server used for UF.