I do not know what you plan to visit, some things are worth the tourist overload, like Prague Castle, some are not - think Venceslas or Václavské náměstí/square or the Staroměstské náměstí - Old town square. There is a traffic renovation that is restoring most of the Vaclavske square, the walking is limitted, traffic is a nightmare, do not visit. Pick a different square to see, like Jiřího z Poděbrad, Náměstí Míru (peace square),... you get your old church old buildingst there too. The National Museum, sittting on top of vaclavske square is awesome and recently renovated but depends on the exhibition and your love of minerals (massive rock collection), huge whale skeletons and taxidermy animals.
Walking is fine in the city center, though people and pickpockets, but subway is cheap and safe and quick and will allow you to visit more places, trams are fine, buses get stuck in traffic. Also one ticket gets you on any subway bus or tram AND some trains for some stops.
I always recommend the zoo, subway plus a bus ride, and hit the opening time/9am time, if you like animals, you can spend up to 6 hours there, even a whole day. The new restaurant complex (though eating mostly outside, limitted seating inside) next to the elephant exhibition is the best one in the zoo, so aim for a nonstandard lunch time - 11am, 13pm and you will be fine.
We utilize bolt ride and ubers, do not get one from the airport, the bus goes wherever you need, goes like every ten minutes, directly to the subway which will drop you anywhere in the city. Just research the ticket purchase, it can be done by card in the bus now, but the ticket inspectors are mean
And if you like alcohol, there is this
https://slivovitzmuseum.com/ with virtual tour and tastings and they have a restaurant with not much food, think finger food czech style, and it is worth the visit though it is a potent booze
For food, lunch is fine anywhere in the city, some fastfoods, like bagueterie boulevard or wok-in ar eok for fastfoods, rest is the same as everywhere. For dinner, either pick a cuisine or go out of prague 1. Also friday-saturday dinner almost always requires a seat booking lately. I was recently in a Georgian restaurant in city center, high prices but lovely food and local performance. Not for everyone (georgian singer singing a pop song was not my jam)
most things and stores accept cards, but having 1000 czk in cash would be wise.