A deployer can only be shared between multiple SH clusters if the clusters have the exact same apps and configurations and use the same secret. See also: https://docs.splunk.com/Documentation/Splunk/latest/DistSearch/PropagateSHCconfigurationchanges#Deploy_to_multiple_clusters
So no, you cannot use a single deployer to manage the configuration of such 3 very different search head clusters. Also a Deployer cannot be used to manage an Indexer Cluster. You use a Cluster Master (also known as Master Node) for that.
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