>>211858190It’s slightly complicated. I would encourage you (and anyone) to master Standard German/Hochdeutsch first, and only worry about acquiring whatever local variety is spoken where you land (and there are many) once you get here.
While Swiss German is virtually everyone’s preferred spoken language, it’s not written. Standard German is the official language, and the one you may be required to pass tests in when seeking permanent residency or citizenship.
Pretty much nobody expects immigrants to be fluent in Schwiizertütsch, but the government almost always requires them to be at least somewhat proficient in German. Most immigrants eventually wind up speaking various hybrid forms, some closer to Swiss, some closer to Standard, and everyone is used to it. Very few immigrants who didn’t grow up here ever become completely fluent in Swiss German. This doesn’t bother most people, but there is a stuffy, mostly older segment of the population who find bad Swiss German irritating. These (assholes) are typically more forgiving of imperfect Standard German.
Most people in most places, though, regard foreigners speaking dialect, even imperfectly, positively. The only exception is when these foreigners are Germans, about whom the stereotype is that they always get Swiss German wrong, in especially offfensive ways, and usually don’t notice it themselves. I think trying to speak Swiss German may be harmful only to Germans.
Swiss German can be socially beneficial, but I see immigrants literally every day speaking Standard German to locals who respond to them in dialect.
