Thank you for your suggestion. We understand it is super important to whitelist specific IP list for ADF as part of firewall rules and avoid opening network access to all. We are working on this with high priority. Once this is ready, we will also add ADF to the list of “Trusted Azure service” for Azure Storage and Azure SQL DB/DW.
This support is planned for SQL DB Managed Instances:
ThanksEvan Barke commented
Yes, this is not a solution. We need it in standard Azure SQL Database!