I have consulted with the engineering team regarding your request for fine-grained control over routing in Quartus. Unfortunately, the ability to specify exact routes to individual wires is not exposed to the public as it requires a deep understanding of the device and routing fabric.
However, you can utilize the RESERVE_ROUTE_REGION feature, which allows you to prevent other nets from mixing into a specified region. While this feature is not mandatory, it is commonly used in Partial Reconfiguration (PR) designs.
If you have any further questions or need additional assistance, please feel free to let me know.
Best Regards,
Richard Tan