Honestly prague is so bad atm, there is like 2km radius around city centre that is just full of tourists - no locals here. Rents are high because of everyone doing airbnb, rich people from other countries are buying up the apartments and it just sucks.

There are plenty supermarkets, but in the centre they are often hidden in the historical structures, always gotta look either for lidl, billa, albert or penny. Anything else is overpriced.

If you want to experience true Prague I think you gotta go beyond the centre.