Steve B - Thanks for the question and using MS Q&A paltform.
Have you tried the steps - you are metioned in the question?
Can you please share more details versions of an Oracle database which you are using?
There are two ways to connect to on-prem Oracle source.
One way is using a self-hosted integration runtime - If your data store is located inside an on-premises network, an Azure virtual network, or Amazon Virtual Private Cloud, you need to configure a self-hosted integration runtime to connect to it.
The second way is you can also use the managed virtual network integration runtime feature in Azure Data Factory to access the on-premises network without installing and configuring a self-hosted integration runtime.
For more details refer to Copy data from and to Oracle by using Azure Data Factory or Azure Synapse Analytics and Connecting Oracle OnPrem from Cloud using Integration Runtime.
Hope this will help. Please let us know if any further queries