Yep, Callie, both are Italian state museums, both are free on that day, and both will be very busy. Honestly? With only one day to spend in Florence there are better things to do than waste time standing in very long lines and be stepped all over by the mob inside. You could possibly drop by mid-afternoon and see how long the queues are? Or take your breakfast and a book to read while you wait and go to your top pick WELL before the opening hour.
The Bargello (which is excellent), Pitti Palace, San Marco (also excellent), Medici Chapels and Palazzo Davanzati are free as well but could be considerably less crowded. I also dug up a previous thread for some alternate, free-Sunday suggestions.
https://community.ricksteves.com/travel-forum/italy/free-sunday-at-uffizi-and-accademia
And there's aways the Duomo complex. Hours on April 2:
Cathedral: 13:30-16:45
Baptistry (a wow!) :08:15-13:30
Museum: 09:00-19:30
Bell Tower: 08:15-19:00
Dome: 13:00-16:00
https://www.museumflorence.com