There aren't any quarantine requirements for Switzerland, Italy, France, and Greece, but it's a longer gap than we're used to:
Arrival in Zurich: 17 Sep 1:20pm
Departure from Milan: 22 Sep 11:09am (spending 4 days 22h on land)
Arrival in Bastia: 22 Sep 12:02pm
Departure from Figari: 26 Sep 9:38am (spending 3 days 21h on land)
As a reference, last season we had: Trinidad and Tobago (~1.5 days on land), Bogota (~1.5 days), Manaus (~2.5 days), Asuncion (~2 days), Paris+Berlin (~5 days), Almaty (~2.5 days), Hyderabad (~1.5 days), Siem Reap (~1.5 days), Manila (~1 day).
I wonder if we could have fit in two legs between Switzerland and Italy, or even on Corsica for that matter?