Sicily - how easy is it to drive

IMO, there is no difference driving in Sicily than driving elsewhere in Italy or other places in the EU. A few years ago, we had a 2+ week road trip in Sicily and it was a blast. BTW, I've been renting cars when visiting Europe for nearly the past 20 years.

We were in Sicily for 2 weeks in May 2022, with a rental car for most of that time. Driving in and around Catania and Palermo is not fun, but much of the rest of Sicily is pretty easy. My biggest concern was keeping below the posted speed limit, and typically I was the only car on the road trying to do that. You won't want or need a car in Palermo or in Ortigia. We visited Ortigia before traveling by bus to Catania where we picked up the car as we left the city. Palermo was the last stop, and we dropped the car at the train station (that wasn't a fun drive) took a taxi to our apartment and walked everywhere after that.

Same as everywhere else in the world. One enters their vehicle and drives. Just don’t enter most hill towns centers because of ZTL because otherwise you’ll get tickets mailed back to your home months later. Stay alert, mind the road rules, because they’re different everywhere, and you’ll be fine. Speaking as one who’s been driving in Italy for 25+ years as a tourist and resident

Learn the European road signs. Many are different from the signs in use in North America.
https://en.m.wikipedia.org/wiki/Road_signs_in_Italy

Learn about the ZTL. Most Italian cities and towns have such restricted zones in the historical centers where only residents with permit can enter. Some hotels inside those zones can get you a temporary permit to unload your car, but you must check with the hotel first. Usually Airbnb hosts cannot. The safest option is to find accommodations outside the ZTL.
https://en.m.wikipedia.org/wiki/Limited_traffic_zone

When driving on multilane freeways, stay on the right lanes. Left lanes are for passing other vehicles only, do not cruise in left lanes. Passing vehicles using the right lanes is not permitted.

There are occasional speed cameras on the road, many are unmanned. Use the Waze navigator to alert you of upcoming speed cameras. Below are the speed camera icons used by Waze.
https://www.waze.com/wiki/UnitedKingdom/Speed_Cameras

I am not sure that a car would be that useful for your itinerary. We rented a car when we left Siracusa and returned it at the airport before we took the train into Palermo.

A car is useless in Palermo and only useful in Siracusa if you are planning day trips.

A car in Palermo is useless and an absolute nightmare, there's more than enough to see in Palermo for three nights, and you could take a bus to Monreale and the train to Cefalu.
As regards Ortigia, again you won't want a car in Ortigia. It depends if and where you want to day-trip - there's a limit to what you can see in thte time available, car or no car
https://slowtravelitalyspain.blogspot.com/2019/06/siracusa-trip-report-october-2017.html

I've airways enjoyed this blog by Cameron Hewitt about driving in Sicily.

https://blog.ricksteves.com/cameron/2018/06/sicily-driving/

As in day trip driving from Palermo and Ortigia? As a tourist, staying in the city center (essential) is at odds with having a rental car available and ready for your daytrips. Parking and traffic would be significant obstacles. So, depending on where you’re thinking of going, a guided tour or a night outside Palermo might be a better choice. Places like Monreale could be even more challenging with a car.

Ortigia is better. You’ll likely have to park outside of Ortigia itself, but you can get out of town pretty quickly. Day trips to the hill towns are doable.

The autostrada connecting Palermo and Siracusa is pretty great, fast and easy. Off the autostrada can be a little challenging, especially with a manual transmission. Sicily is quite hilly through the interior, and you can find yourself on some tight, twisty roads. That was most difficult aspect for me. It had been quite awhile since I had handle a stick shift under those conditions.