The supported use described for Surface docking stations is to connect a Surface device to monitors, Ethernet, audio, and accessories. The documentation does not state support for using a Surface Pro docking station as a dock for an iPad.
Surface docks are described as connecting your Surface through Surface Connect or USB-C/USB4, depending on the dock model. Examples in the documentation include:
- Surface Dock and Dock 2: connect a Surface to external monitors and accessories.
- Surface Thunderbolt 4 Dock: connects a Surface via USB-C.
- Surface USB4 Dock: connects a Surface via USB-C/USB4.
If the goal is to connect an iPad to a monitor, that is not covered by the Surface dock documentation provided.