David-
Since your subject line does say you want suggestions I’m going to go with that. I remember well planning our first trip to Italy- we only had 17 nights, so a whole week less than you have- how lucky you are!
I got the books, the maps, I looked at all the suggested itineraries and said “I want to go to all of those places” then the further along I got in planning- with some awesome help from this forum- I realized that was simply not practical. Not even sure it would have been practical if I had 23 nights as you do. (Count your trip in NIGHTS, a 2 night stay really means just 1.5 days to enjoy whatever location you are in)
This is a vacation not a Death March.
I somehow missed that you have Venice in your plan. Wonderful. But you also have 4 “water/coastal” locations- Venice, Como, CT and Amalfi. Pick 2 or possibly 3. I don’t know what is more important to you so research CT- make sure you know how crowded it might be, what will you do if the weather is lousy? research Como- is there enough to do there to warrant 2 nights plus the nights in Milan. Is Milan a bigger priority than Venice? The sights you listed in Milan probably need 2 nights.
Venice is a fantastic entry to Italy and a great place to get over jet lag. Easier to fly IN to than out of. If you can start your trip there you won’t regret it. Venice is unique, there is no other place in the world like it. Give it the 3 nights it deserves. Minimum.
Florence needs a minimum of 3 nights- hopefully not over a Monday because many museums are closed that day. Add 1 night for every day trip you take from Florence.
We’ve never bothered with Pisa. Too many other places more interesting.
You are renting a car but not really using it where it benefits you most. Tuscany is where you want the car. You can visit Montepulciano, Pienza, Montalcino with a car on your own- better yet- stay in Montepulciano.
Sorrento/Amalfi area has so much to do. We spent 9 nights in the area and are returning this Sept for 4 more nights- mainly just to chill. You’ll get a bit of everything there- views, water, hiking, relaxing, great food, fun shopping and wandering.
Pompeii is huge and exhausting- give it a day. Capri is a day. Naples is a day. All super easy day trips.
Positano was a half day for us. Not impressed. Ravello is lovely- give it a full day so you have time to walk out to Villa Cimbrone. Fabulous iconic Amalfi views.
This was our first trip. It was the perfect first trip. For us.
Venice 3 nights
Florence 3 nights
Picked up car and drove to Siena along the Chianti Road
Siena 2 nights- no day trips- just stayed put in town
Montepulciano 2 nights- day tripped around Tuscany/Val D’Orcia- can not wait to go back but car rental rates are outrageous this year ;)
Drove to
Assisi- 2 nights- day tripped to Spello on 2nd day- lovely little village, nobody there but us.
Then we dropped the car in Spoleto and trained to Rome for the last 5 nights. You can never have enough nights in Rome. Seriously.
We started our 2nd trip in Rome and will end this upcoming trip in Rome- we love it.
We really wanted to go to Orvieto but had to cut that. We are finally going to Orvieto on our next trip. It’s not going anywhere. Assume you will return.
I am not at all sure what the attraction of Civita di Bagnoreggio is to be honest.
We are actually flying into Milan this time but not spending any time there. Too complicated right now to score Last Supper tix- we’ll save it for “next trip”. Just so happened that was our best choice for a flight and at the time a COVID tested-no longer need that. We’ll head to Stresa on arrival and use that quieter place to get over jet lag.