I don’t know why Alex would go to Switzerland without Jo, so this scenario would probably result in Jo leaving too, which is not ideal.
When Sandra Oh left Grey’s Anatomy, Cristina Yang wasn’t killed off, she took a job at the Klausman Institute for Medical Research in Zurich, Switzerland.
This is another tricky scenario for Jo, since I don’t see Alex going there without Jo unless they broke up off-screen.
Switzerland would be quite a long-distance relationship from Seattle, so this is the least likely scenario to work if 1) Jo stays at Grey Sloan as a main character on Grey’s Anatomy and 2) Jolex gets to stay alive as a relationship.