Boat tour to Capri or extra day in Rome?

Traveling in mid June and debating whether to do an extra day in Rome for a total of 2.5 days (June 19-21) or taking a day from my time in Rome and doing a 8hr boat tour from Naples to Capri on June 19.

I’d never been to Italy before and I want to hit all of the big things in Rome: the Vatican museum, the Sistine, St. Peter’s basilica, the pantheon, the colosseum, have time to explore and shop and I don’t think I can fit it all in a Saturday and half the day Sunday if we do a boat tour to Capri.

Is the boat tour worth it? Is staying in Rome an extra day worth it? Help 😅