savemii VS BotW-Save-Manager

First you need to backup your saves with the saveMII mod (for WiiU) then use a tool for windows called "BotWSaveManager", after the conversion you inject the new file into the switch using the checkpoint mod. This process can be done in reverse order if you want to take the save from switch to WiiU.

use cemu, and use https://github.com/DeltaJordan/BotW-Save-Manager to convert ur save from switch to wii u

Trust me, when you go to Cemu, you'll be more than happy, especially if your PC specs are anywhere near middle end (something like RX 6600/ RTX 3060), you'll see the benefits, the graphic packs let you change the view distance of almost anything, there are ultrawide settings, color profiles that make the game look much better, you can change the shadow resolution and render distance, and there are also save data conversion tools to switch over your save (I can't say how well they work firsthand but they exist).

Next, I used this save manager to convert my Cemu Wii U save to a Nintendo Switch save for Yuzu.

There's a save converter if you want to give it a try: https://github.com/DeltaJordan/BotW-Save-Manager

Google, my friend. https://github.com/DeltaJordan/BotW-Save-Manager you'll need botw on yuzu tho i think

In another reply someone recommend the following converter to havoc your wiiu save usable with the switch version: converter

I used this to transfer my save to cemu