Since this question is specific to the ESS on Elastic Cloud, you might be able to get a more competent answer via the support form in your account. To my limited knowledge the monitoring data can only be shipped to clusters local to the region and account.
The stack monitoring feature (and visualizations too, of course) can search in indices from different clusters via cross-cluster search (CCS) regardless of the underlying infrastructure. If you only care about being able to access the data and not about the location of the data, this might be sufficient for your use-case.