Just back from Italy, ate very well, mostly
Firenze on the Duomo side of the river is all touristic, even in places where the food quality has been kept up any real atmosphere is absent.
In the last couple years they’ve done over the market and the upper level (1st floor in European parlance) has been converted into a “food court” (If you’ve been to the Mercato San Miguel in Madrid they are trying to copy that, less successfully) and the ground floor market is a pale shadow of what it once was, that said Nerbone is still there and worth a visit for a sandwich (order the Lamprodotto sandwich, just trust me) but yes it is utterly swarmed with other tourists [when I was there a couple years ago there was an Italian trying to jump the queue and beaking off to the staff about why they were serving all these foreigners ahead of him, a real Italian].
Trattoria Mario is another one of the famous places and while it’s swarmed with tourists too they are holding on tooth and claw to as much of the tradition as they can, hand written daily menu, hearty Tuscan home-style dishes, get the peposa if it’s on.
Other than that head for the other side of the river, Trattoria La Casalinga comes highly recommended by my Florentine insider friend although it’s in all the guidebooks so it will get ruined soon enough I guess.
Also swarmed with tourists of course and has been on some level since the 14th century but there are some gems
For lunch take a vaporetto ride to Burano and go to Da Romano (or if you are there on the day they are closed, Al Gatto Nero), this trip we just did a day trip into the city and instead of regular meals just grazed the chicetti at a selection of bacari (Cantina Do Mori is mandatory, it’s been there since sometime in the 15th century and feels like it) there are a bunch of good ones in the Rialto area, Cantino Do Spade, All’Arco, and more. I also like Gia Schiavi in the Desodoro area.