We arrived at the Florence airport six days ago, after getting a rapid Antigen test at a lab in Chicago (with negative results) the day before. Airports all competent, but not a lot of social distancing. COVID papers galore, but I'll answer specific questions rather than go into details about that.
Florence is slightly less busy than in 2019, but not much! No real masking outside, and a fair amount of "COVID theater" in the museums, with people either removing them frequently or letting them hang halfway down their mouth. Social distancing in the Uffizi is non-existent.
Bus to Siena was near full-- again no social distancing. Siena was a little more subdued than 2019, esp. after day trippers have left. Easy to social distance there. At outside all but once.
After returning from Siena, got our negative antigen tests near the Duomo at a pharmacy for 22 euro each with ease. We fly home on Tuesday morning.
(What follows is just our personal opinions, not to be used as professional travel advice).
Our overall impression: Italy is back. We felt mostly safe, but are fully vaccinated and careful to mask up whenever we are indoors. Life is generally back to normal here (with a few extra steps). We are so happy we chose to come now! It was the trip of a lifetime.
BUT, if you're nervous about social distancing, lack of mask consistency, and crowds, you're going to have to come to terms with the fact that there are many people here from around the world, and you'll inevitably rub shoulders with them at some point. If you're preferred risk level is very low, I'd say you'll be happier at home. But you'll probably be safer here than in Florida, Vegas or many other parts of the US.
I'll try to answer any questions if I can!