darren, it would have been helpful if you had put your home city in your profile - then we might have a hint of whether the purpose-built resort city of Sorrento is actually worth visiting for you. Although we (not you ... ) have recently been scolded here for suggesting that an OP change their itinerary, you have asked us: "Venice" or "No Venice"?
I cannot imagine omitting Venice and insisting on the Amalfi Coast. Actually, you could consider Cinque Terre, which is not so much of a hike. In addition, Venice is in physical danger, and hints of future restrictions on daily visitor load have surfaced. Go now. The puzzle to me is that you scheduled more nights in Florence than in Rome, which I have been to three times. If you care about one of the principal centers of Western culture, why do you care so much about one of the centers of United Kingdom sun-seeking tourism?
To be clear, my wife and I spent 5 nights in Sorrento, on our fifth trip to Italy. My highest priority was Pompeii, which was worth it. We spent 240 Euros for a car and driver for an 8-hour visit to Positano, Amalfi, and Ravello. Are you aware how much extra effort it is to visit the AC from Sorrento? (Lots of people do so, I'm not trying to talk you out of it.) Two years later, we visited Capri on two consecutive days. While it was important to "tick that box", the degree of luxury is far below that of a non-Beaches (i.e. mass tourism) destination in the Carribean. As Lonely Planet wrote, "seeking the glitterati, and finding only their prices.