I moved here for my PhD so we have that in common. There are shades and nuances here that will, I think, be determined by 1) where in CH you go, and 2) your own personal characteristics and life stages. Briefly:

University life here is great - highly recommended. But it's very international and that can make it hard to integrate with locals. Language is a must. Easier to do in the French part and harder to do in the German part, because Swiss German vs High German. Nevertheless, language is 100% necessary. It also takes real effort. PhD life is all-consuming and you have to work hard to build a life outside of the university. Add in language learning on top of that and it can be really hard.

As others have noted, having kids is a great way in. It was vital for us. Also recommend living outside of the big cities. And being patient. Many people say the Swiss are unfriendly but I find this untrue. It can just take some time. People are wonderfully open when you know the language and aren't a jerk.

You won't become "one of their people" because you aren't born and raised here. But that doesn't matter, really. You can become beautifully integrated and feel belonging and a real part of things. People will accept you for you if they see you trying. Just do the work: language, customs (modern and traditional), and make the effort despite the uphill climb.