Smaller shops are open shorter on Saturdays, e.g. until 2 p.m. - 3 p.m., but large shopping malls (for example, Złote Tarasy or Arkadia in Warsaw) are open, just like on other days of the week, until 10 p.m. Supermarkets such as Biedronka, Lidl etc. are also open for a long time, until 11 p.m. As for Sundays, on non-trading Sundays it is as you wrote, it is very difficult to buy something. Fortunately, I have 2 grocery stores near me that are open on Sundays, so at least I can do this shopping then. It is a pity that Sundays have changed so much, I hope that the next government, when it is elected, will introduce the customs that they used to be, where you could shop on Sundays and the shops were open.
Yes, I liked the Aperol Spritz. It was very tasty 😊 Although it's not my favorite drink.