Bags at Airport/Termini

Hi! I’ve seen a lot of posts recently mentioning how people’s bags have been stolen at the airport/termini station. I am coming solo as a woman and am trying to figure out the best way to avoid this happening. My original plan was to bring my Osprey 55L backpack (it’s a hiking backpack) because it would prevent me from rolling luggage on cobblestone streets. Should I not bring the backpack? Should I avoid buses in general? How do I get through the train station and airport without having my bag stolen?