don't do this. Since 1999, email providers in Switzerland are forced to keep all logs and data for one year (currently in discussion to prolong this to 5 years) and hand all data over at the authorities request.

If you don't comply you will be punished by fines or even jail.

I once (early 2000s) received one of these orders and I honestly don't remember whether it had a judges signature, but I think it was just some police officer signing it, so I can't be sure whether there was (and is) any court oversight.

If you want your conversations to be confidential, don't choose a Swiss provider.