Career Advice: Would you take a step back to advance forward?

This is a common position and it's really a choice each person has to make on their own because it really does vary person to person. Let me give you an example, when I was younger I was a pretty good programmer and I rose through the ranks very quickly and got a little bit of notoriety. I was self trained but I had some mentors that were real heavy hitters and they taught me a lot. Anyway I was given the option to go work for a very well know SV god father where I'd be a mid-level guy. The other option was to go work for a no name startup where I could sail the ship. At the time I had just gotten done working for another start up and I was looking for something better so I went with being an underling at a really big company. It was really cool to do some bleeding edge work and to work with people that were absolute geniuses, but I am not a geniuses despite what my mother thinks. It was like going from playing sports in uni vs playing sports as a professional, everyone was really, really good so instead of standing out I was just another brink in the wall. For me this caused me to really step up my game just to keep up with the crowd, something I wouldn't have to have done at the startup. It was a doubled edged sword, there was a lot of growth on my end but no rewards, I was just average for the company, if I had went the other direction I wouldn't have had to step up my game but I would have been the top dog. It's big fish/small pond syndrome you have to pick what you want to be, neither is wrong.

Adding to other advice here: make sure you know how much salary will be in your pocket after taxes and living expenses. Switzerland is an expensive country, and comparing just the absolute number could make you feel very miserable once you are living there.

Other than this, titles are irrelevant IMO. Probably they just put you into the title with the same salary band.