Hello! Traveling around Europe is wonderful, because there are so many amazing sights that can not be revisited throughout the summer. From the cities you proposed, I would go to Barcelona, because it has long attracted me with its beauty and good location. I heard from friends that romantic Paris can be boring, and Rome is always crowded with tourists. Well, if you want my opinion, go to Ukraine to see Chernobyl
https://chernobyl-visit.com/ - the site of the largest man-made disaster. You will definitely not forget this!