Cash is king. Am surprised at the number of restaurants not accepting Visa - five so far, and none with any warning. They all had the little Visa stickers on their doors.
Taxi drivers, too. And even the one train ticket machine in one small town wouldn't take a Visa for whatever reason.
A wine tour operator said no to Visa and wanted 30 percent (plus fees) deposit through PayPal, or Wise or Revolut, and remainder in cash. Never heard of Wise or Revolut. And I don't use PayPal. Not used to carrying around 400/500 Euros at a time. And we haven't heard back whether they'll do the tour without the PayPal deposit.
My lesson is carry a wad of cash, which seems to be contrary to all past experience in Italy.