Can I use Emergency SOS by satellite in Switzerland?

Yes. See the four references to Switzerland in the following from Use Emergency SOS via satellite on your iPhone - Apple Support

Emergency SOS via satellite availability

• You need an iPhone 14, iPhone 14 Pro, iPhone 15, or iPhone 15 Pro with:
  • iOS 16.1 or later in the U.S. or Canada
  • iOS 16.2 or later in France, Germany, Ireland, and the U.K.
  • iOS 16.4 or later in Australia, Austria, Belgium, Italy, Luxembourg, the Netherlands, New Zealand, Portugal, Spain, and Switzerland
• You need to be in a place with no cellular and Wi-Fi coverage.
• You need to connect to a satellite with your iPhone
• Emergency SOS via satellite is available in Australia, Austria, Belgium, Canada, France, Germany, Ireland, Italy, Luxembourg, the Netherlands, New Zealand, Portugal, Spain, Switzerland, the U.K., and the U.S.3 
• International travelers who visit a country or region where Emergency SOS via satellite is available can use the feature while visiting, except if they bought their iPhone in certain countries or regions4.

1. In the U.S. and Canada, call or text 911. In Australia, call or text 000. In Austria, call or text 112, 133, and 144. In Belgium, call or text 100 and 101. In France, call or text 112, 15, 17, 18, 114, 119, 191, and 196. In Germany, call or text 112 and 110. In Ireland and the U.K., call or text 999 or 112. In Italy, call or text 112, 113, 115, 118, and 1530. In Luxembourg, call or text 112, 113, 12112, and 12113. In New Zealand, call or text 111. In Spain, call 112. In Switzerland, call 112.

2. You need iOS 16.2 or later to connect to emergency services via satellite when you call or text 15, 17, 18, 114, 119, 191, and 196 in France, 110 in Germany, and 999 in Ireland. You need iOS 16.4 or later to connect to emergency services via satellite in Austria, Belgium, Italy, Luxembourg, the Netherlands, Portugal, Spain, and Switzerland. The availability of these additional emergency numbers might also depend on your cellular carrier.