You can order a data SIM card for Switzerland from Digitec for as little as CHF 10 per month. Without further costs. Unlimited data volume. You can extend the additional months into a subscription and cancel at any time during the current month. There is a good description. The SIM does not cost extra and runs perfectly via Sunrise. I've had the best reception in Switzerland so far!
The device also works perfectly.

You need a SIM card from a mobile phone provider. For example, I have a data subscription at a special price of CHF 20 per month.