The Wii U walked so that the Switch could run. I'm glad to see renewed interest in it. Now if we only had a decent emulator. I know Cemu exists but the compatibility of most games I want to play with it is atrocious.
Dolphin only supports Wii games, not Wii U. This is part of the reason the Wii U flopped is that people thought it was just a peripheral for the original Wii and not a separate new console.
Dolphin is indeed fantastic for Wii/gamecube games though