If you use Emunand to mod smash and either stay offline or use switch lan-play to play online you won't get banned. Just make sure the game is still legit on Sysnand. Emunand is a copy of your switch software that you can do whatever you want on it, dirty the nand, etc. It will keep all your hacks and mods away from your normal switch games. Just make sure you install Incognito, 90DNS, and stealth mode if you have SX OS on your Emunand to block it from going online on Nintendo's servers because your Sysnand will be banned as well. Switch lan play is software that takes your switch LAN games or local wireless games and tunnels the connection through the internet, so it acts like you are sitting in the same room as each other.