V2 Rest API is recommended for on premise applications to access Object Store. It also comes with overhead of encryption and security of using rest api. With Object Store v2, the API call is localized to the same data center as the Runtime Manager app.
But in this case requirement is to access the OS of other mule application and not the same mule application.
You can configure a Mule app to use the Object Store REST API to store and retrieve values from an object store in another Mule app.
However, Object Store v2 is not designed for app-to-app communication.

To migrate Mule applications from CloudHub to Runtime Fabric (RTF) while maintaining the same automated CI/CD deployment strategy, follow these steps:
* Add runtimefabricDeployment Profile: Add a runtimefabricDeployment profile to the pom.xml file in all Mule applications. This profile will include the necessary configurations specific to RTF deployments.
* Modify CI/CD Scripts: Update the CI/CD deployment scripts to use the new runtimefabricDeployment profile. This modification ensures that the deployment process will correctly reference the RTF-specific configurations when deploying applications.
* Keep Configuration Files Unchanged: There is no need to change the pom.xml and Mule configuration YAML files other than adding the runtimefabricDeployment profile. This maintains consistency and reduces the risk of errors during the migration.
This approach ensures a smooth transition to RTF while leveraging existing CI/CD scripts with minimal changes, maintaining the automated deployment strategy.
References
* MuleSoft Documentation on Runtime Fabric Deployment
* Best Practices for CI/CD with MuleSoft