7 days in Italy

I am traveling to Italy on the 4th of February ( in two weeks) I only booked the flights i will land in Rome and the flight to my home country will take off from milan.

I am staying for full 7 days, I was thinking to explore rome , Florence and Milan.

I wanted to ask if you would recommend airbnb or hotels for these cities? And also what is the best area for accommodation in rome? And did anyone rented a car in Rome? If yes how was the experience? Is it good or trains are better? This is my first time in europe so I don’t know if a car would make things better or worse.