Hi,
Yes, you are right, the example is only available for hardware. There is no test bench by the factory. Sorry for the inconvenience.
As a workaround, would you mind to try out in hardware to see if it is working on hardware? You can start with this example design or simplify the design for testing purpose. With a working simple design on hardware, you may create your test bench and simulate it in Modelsim. This could help to narrow down any potential simulation only problem and at the same time serve as workaround to ungate your progress.
Please let me know if there is any concern. Thank you.