This should work as you describe. The empty tables are most likely the result of the Mendix runtime doing a regular database synchronization from your app, not from a partial copy from the SQL Server database. The runtime should do a database migration if both
Note that the SourceDatabaseJdbcUrl uses database specific parameters that can be found in https://learn.microsoft.com/en-us/sql/connect/jdbc/building-the-connection-url?view=sql-server-ver16, it does not recognize SourceDatabaseName, which is a Mendix setting. But as mentioned above an incorrect URL should result in startup failure.