That's because you have a Mk 2 Ka, and it has zero relationship to the original. The Mk 1 was already an old design when it launched (it’s based on the Mk 3 Fiesta, a model that debuted in 1989), and so lacked the level of rustproofing that you'd expect from a 1996 car. Against that, it was as light as a 1989 car too (about 900kg), so it was quick even with low output engines.
The second-generation Ka (2008-2016) that you have is based on the FIAT 500, and was developed and built for Ford as a “white label” project by FIAT in Tychy, Poland. Despite the Ford “Duratec” and “Duratorq” branding, the engines used are the FIAT 1.2 FIRE petrol and 1.3 MultiJet diesel: the only mechanical difference between a 500 and Ka is that the Ford had a modified rear suspension, but this change was later merged into the 500.
The 2016 onwards Ka+ was a real step backwards. Ford gave up on the idea of small cars being interesting, and adopted a more American attitude that small cars were only for people too poor to buy something bigger: like the Nissan Micra Mk 3 (from 2010), it was a model designed for emerging markets, drafted in to Europe to sell on price alone.
Try one of the Abarth 500s - it's the same fun to fling around, but with up to 180 bhp driving the wheels. That doesn’t sound like a lot, but in a car that small, it’s insane.