Small group tours are more personalized and fun than those large crowds  and can handle better private tours in Rome (so everyone can follow the tour guide). You can even arrange a private visit where you tell the guide what you want to see and they arrange the day for you.

If you  never did a tour in Rome before, but do not want to do an arranged package tour where you travel with the same group for the whole trip, consider doing an independent trip to understand better the legacy of Rome.