Are you trying to use your gamepad as a second screen while you emulate Wii U games on your PC? Unfortunately, I don't think that has been done yet. I believe the Wii U uses Wifi to send video to the gamepad and no one has made PC software to handle that yet (to my knowledge).

I had heard of people using the Gamepad to mirror the game playing on their PC.

If you are trying to use your gamepad as a second monitor for Wii U games you would probably have better luck getting a Steamdeck (Youtube link may contain helpful comments).

https://www.youtube.com/watch?v=rW0FvU4IB-w

I sold my Wii U already so I don't think I can be of actual help to you.

[–] nek0d3r@lemmy.world 3 points 3 months ago

Yeah, effectively I'd want to use it as you could on Wii U, both displaying the second screen and interacting with the touchscreen. Splatoon in particular is extremely underrated with second screen use, being able to see and interact with the map in real-time is so much more useful than blocking your screen in future Splatoon games