Florence museum reservations are sold out. Now what?!

They're not sold out of tickets: they're not selling them at all.

The Italian State Museums (The Uffizi and Accademia are both State museums) are free entry on the First Sunday of each month. So, you go stand in line...which could be very long. Is there any other day you'd have in Florence in which to visit them?

https://www.uffizi.it/en/events/free-entry-sunday

Kathy beat me to it
That's the free Sunday so expect crowds and a long wait

(This is OPs only day in Florence)

Thank you for the clarification on the free Sunday! Is it difficult to find a good quality restaurant open on Sundays for a dinner reservation? Two stars or perhaps three stars?

It shouldn't be difficult. This thread has a list of restaurants posters can recommend, although not all of them will be open on Sunday (my own entry on that list isn't.) Roberto has contributed some which he states are particularly economical: search their websites out on the net to check their hours? If you find one you'd really like to try, make a reservation; early Sept. will be very busy!

https://community.ricksteves.com/travel-forum/italy/top-restaurants-in-florence

Dang, sorry you're only there on a First Sunday.

Rose’s

Via del Parione, 26 Rosso, 50123 Firenze FI, Italy

Two stars or perhaps three stars?

Out of curiosity, do you mean two or perhaps three MICHELIN stars?

Family-run restaurants may close on Sunday evening, but I bet most of the 11 starred restaurants in Florence remain open.

As Dario mentioned, there are 11 Michelin starred restaurants in Florence, but only 2 have 2 stars and 1 has 3 stars. You can go to the Michelin Restaurant site to check their closed days. Some, but not all, of the 1 star restaurants should be open on Sundays. You'll want to reserve your meal well in advance.

Oh, you meant 2 or 3 MICHELIN stars. Doh.

Thank you all so much