So Nintendont was updated to support the GC adapter for Wii U

Hyperkin 4-Port Controller Adapter for GameCube Compatible with Nintendo Switch/ Wii U/ PC : Video Games

Third party Gamecube controller adapters for Nintendont.

Can You Play GameCube Games on Wii U & How to Do? - MiniTool Partition Wizard

GameCube controller support comes to Nintendo Switch - Polygon

Can someone please help me work a third party GC adapter with nintendont

Controller Adapter for Gamecube- Compatible with nintendo switch, wii u, pc, You can play the super smash bros on Wii U and Switch, Plug the two usb

Y Team Controller Adapter for Gamecube, Compatible with Nintendo Switch, Super Smash Bros Switch Gamecube Adapter for WII U/PC with 4 Port

raphnet. - N64 controller to Wii/Gamecube adapter (v2)

Nintendont Controller-Configurations, Page 4

WHOA! GameCube Adapter Works on Nintendo Switch! - We Show it Off!

raphnet. - N64 controller to Wiimote adapter

4 Port GameCube Controller Adapter for Nintendo Switch Wii U PC Super Smash Bros

What is this thing? 😅 : r/Gamecube

Switch to “Wii U” or “PC” mode by using the switch located on the side The GameCube Controller Adapter allows you to connect up to four GameCube

Mayflash GameCube Controller Adapter for Wii U, PC USB and Switch, 4 Port

Gamecube Controller Adapter Switch Gamecube Controller Adapter Wii U - 4 Ports Game - Aliexpress