Try this?
https://gbatemp.net/threads/botw-save-converter-switch-wii-u.499483/
Setup
- Download and install the DotNET 6.0 Runtime for your system: Windows x64 or Linux
- Download the latest release of BotwSaveEditor.
- Run BotwSaveEditor.exe and bypass the smartscreen warning. (This warning is caused by the unsigned .exe. Signing applications can become expensive, so it is impractical for community project such as this.)
Usage
Desktop Application
Normal Method:
- To open a save, use File > Open Save Folder (Ctrl + O) or double click the UI to browse for a WiiU or Switch save folder; alternatively, drag the save folder over the UI.
- Once the save has opened, click Convert and browse for an empty folder to save the converted files to.
- A debug log will appear and log the converting process.
- Once it has completed, and there are no errors, a prompt will appear saying the conversion was successful.
Quick Method:
- Quickly convert a save by using File > Convert Save (F3) and navigating to a WiiU or Switch save folder.
- In the second folder selection prompt, browse for an empty folder to save the converted files to.
- A debug log will appear and log the converting process.
- Once it has completed, and there are no errors, a prompt will appear saying the conversion was successful.
Console Application
- Drag and drop a WiiU or Switch save folder over the console window as prompted.
- Wait for the save to process, then drag an empty folder over the console window to save the converted files to.
- Wait once more for the completion message.
After you convert it you'll wanna use saviine... probably...
https://gbatemp.net/threads/release-saviine-wiiu-savedata-tool.399833/
...or you can FTP your savefile to your Wii U if you know the right path/directory.