There are thousands of restaurants in each of those cities, and people on this forum are mostly North Americans who, even the most frequent travelers, have tried just a handful in each of those locations. Also their personal tastes will be subjective and may not match yours, so no matter what suggestion you get, it will be the subjective choice of one person who has tried a subset of less than 1% of the restaurants available in that city.
In the old days I used to trust the advice of construction workers and other laborers in Italy. They always knew the best value restaurants at reasonable prices. Nowadays, since 100% of construction workers and laborers are Eastern European immigrants, not necessarily knowledgeable of Italian cuisine, I rely on websites.
I don’t like TripAdvisor, especially for famous cities like the ones you mention, because it is heavily used by non Italian tourists, who may not have a clear idea of what good Italian food should taste like. If I want a good Japanese restaurant in Tokyo I ask a Japanese, not an Argentinian tourist.
For Italian restaurants, in cities I don’t know, I use www.ilmangione.it. (Il Mangione means The Big Eater, which describes me a lot). It’s in Italian only (I think still is) so the people voting their preference in that site are likely Italians. For Florence I trust the advice of friends and relatives there. But I noticed that most of the restaurants I, my family and my friends like to go to in Florence are listed in Il Mangione website, and that reassures me that it is indeed a good website. Filter by ranking, but also take note of the average price in Euro. Some are cheaper than others.
Good luck.