This repo has block lists for your Pi-hole/ emummc.txt that can help you set up a method to block all communication with Nintendo. This will stop any updates and reporting to Nintendo, but it will prevent use of the eShop and online games.
You can find a very well written guide to do this [here](https://nh-server.github.io/switch-guide/extras/blocking_nintendo/)
Feel free to submit a pull request if you find more hosts, and I will happily review and merge to this repo.
