I did it and didn't get banned, but there is no wumpa coins cheat because the wumpa coins are all stored server side. I used some cheats to help me in story mode.
To farm wumpa coins, you don't need a modded switch, just need a modded controller with turbo. You need to go to crystal challenge, the map is lab basement, and make sure to play on hard mode. Once the game starts, turn on the turbo button the A button, and tape the A button down. This will make the controller press A over and over again, which will keep restarting the game. At the end of each game, even if your character isn't even moving you will earn 7 wumpa coins. Let this run while you are sleeping or whatever.