Solo, Firenze Card (city museum pass) works.
For a packed three days hitting many of the big museums, the card streamlines reservations and lets you skip ticket-buying lines. The catch: at ~€85 it only pays off for genuinely intensive sightseers, the Brunelleschi dome complex needs a separate ticket anyway, and many of the headline museums are closed Mondays — so a short or relaxed trip will lose money on it. Do the math against your actual list first.