There is already one private exploit that has been confirmed to work up to firmware 4.1 (and up to firmware 6.0 but may involve more work) that we all know as Deja Vu but there is currently no estimated release time.
All it takes to get banned is connecting for one second. However, the ban itself may not be delivered instantaneously. It may take sometime between a day to a year before you are banned.
I see. In that case, I just need to link a Nintendo account and be offline forever. Once I have the account linked, it'll stay with me forever.
By the way, say I have account linked to 6.1.0, and in future I use ChoiDujourNX to update to say 7.1.0. Will updating via ChoiDujourNX still keep my linked account? or does it wipe everything?