Just wanted to know the recommended way of Publishing the model changes in flowable.
I believe we use RepositoryService to create deploymentBuilder and deploy from there to publish the model changes.
Also there is a modelRepository, but that planning to use for getting the model data
If by models you mean process definition models then yes the RepositoryService via the DeploymentBuilder is the way to create new versions of your definitions.
The ModelRepository that you are mentioning is not part of the engines, but rather the Modeler UI application.