Thanks for sharing your approach to handling data security in your maps. The use of views and leveraging the public sharing feature while keeping the data source layer private is indeed a practical method.
In my previous workflows, I've used to securing maps using proxies and ensuring a certain level of access control.
However, as we transition to the ArcGIS Experience Builder and the portal environment, I've noticed that the dynamics are a bit different and proxies are not applicable at the ExB level as far as I can see.
Thanks again for your input!