Suppose I have an Azure SQL Database Elastic Pool and I am accessing it from an Azure Web App via Firewall rules and everything is working fine.
Now suppose I want to add a new Private Endpoint to the Azure SQL Database Elastic Pool. This would NOT block access via the existing Firewall rules / access outside of the newly created Private Endpoint - is that right?
In other words, adding a Private Endpoint is not saying that access should now be Exclusive through the Private Endpoint but that the Private Endpoint is accessible and existing access channels are also still accessible - is that right?
I would suggest to carefully read the following article which basically answers your question. By default, adding a private endpoint would not block access to the public endpoint but it all depends on the connectivity settings that are configured.
https://docs.microsoft.com/en-us/azure/azure-sql/database/connectivity-settings