Pre-COVID, I knew of someone who visited the campus for the first time in her third year. She had worked from home the entire time and only came to the campus for a student conference. So I would assume that you can work remotely and Zoom call your supervisor. However, it can vary a lot depending on the supervisor, university and the funding situation. I think you should apply as normal and ask at the first opportunity.
If you are asking if you need a Swiss address for the during the PhD, I have no idea.