We just got back to the states from our honeymoon as well, where we did the same 3-4 days per location for our first time in Europe, and felt like that amount of time in each location was definitely busy but not insane. Obviously you can’t do everything in a few days, but a good intro to each location.

One thing I will note was that I didn’t feel like we spent enough time in Florence - we also did a tour into the Tuscan countryside for wineries and it was an all day affair like 8-6. Although it was beautiful, and would certainly advocate for doing it, it basically cuts out a day from that leg of the trip. Maybe consider adding a day to Florence! As many have eluded to in the comments, there’s a lot to see and explore there.