I believe just today Switzerland lifted mandatory quarantines for anyone who tests positive for covid. The UK covid rules say they suggest or recommend quarantining with a positive test and Sweden says all covid restrictions are lifted in the country, which implies no mandatory quarantine as well, though I'd like to see an actual statement saying no quarantine to be sure. My point is, for travelers who are afraid of a positive test on their way back to the US, perhaps ending their trip in such a country might be a good idea.
I'm not suggesting acting irresponsible, but I think if one had a positive test for their flight home it would be nice to deal with it without going into a mandatory covid quarantine hotel, like some Americans have had to do in Italy. On another forum I've been reading about some rather troubling and challenging experiences related to this, and personally I'd rather be handling things and quarantining responsibly on my own terms like our family had to do at the start of this year for instance. Put another way, if someone was doing an Italy Switzerland combination trip ( a great idea by the way), I'd say by all means start in Italy and end in Switzerland.