What i was thinking too.. Both Zurich and Geneva are great in winter and late summer.. For Zurich we really like Neues Schloss Privat hotel and Geneva, the RitzCarlton which is right on the lake. So many things you can do: from some interesting chocolate tastings plus the best fondue places in the world in my opinion a few of which also overlooks the lakes…
Both very enjoyable cities and you’re not far from going into the Alps for a great lunch/dinner and unbelievable views.