There are several ways to edit saves on real cartridges, check out the tutorial. https://projectpokemon.org/tutorials/save-editing/managing-nds-saves/
Once you got your save file you can open it in PKHeX, go to Misc Edits > Pokewalker and select Unlock all, you don't need the wondercards. https://projectpokemon.org/home/files/file/1-pkhex/