Welcome Retirement_Rookie from a neighbor to the south in Switzerland (Lugano, in the Italian speaking canton of Ticino). The dual tax situation can become complex, especially when accountants in your new country don't know much about the tax treaties or the details of IRAs, Roths, or 401(k)s.
I have found an extraordinary amount of misinformation, rumors, and myths concerning what is taxable in the US vs. Switzerland vs. both. It's always best to do your own due diligence; for me that consisted of a lot of google research, talking with other expats, and conversations with our tax accountant. We use one because the forms are only in Italian here and it would be easy to screw up!
We've been here for 9 years now and loving it in Europe. We have permanent residency and plan to apply for the Swiss passport as well. Just returned from a 12 day trip to Cornwall in the UK, via London. EasyJet from Milan (just to our south) to London was 120 euros roundtrip for both of us together, and that was paying for emergency exit seats. Hard to beat that!
-BB