We can’t provide you the guarantee that you won’t be banned.
There’s always a chance.
I’ve brought my CFW Sysnand V1 Switch and used it online for years, and not banned. But I’m just a guy.
You can minimise the risk, but can never mitigate it. Don’t install stuff that aren’t normally possible on a Switch, don’t pirate stuff, only use external homebrew apps via homebrew launcher (don’t install to your Home menu), and follow the variety things on our Discord pins, and you *probably* would be okay.