I'd say your prep for rounds 1 and 3 are solid, the Grokking book really helped me out. For round 2, I've heard people get different experiences, some of it was just theoretical, identifying classes, services, etc. but some were also expected to code the solution. For me, I was expected to code it. I don't remember the question I had exactly, but it was something like: Design a coffee maker machine class with a coffee maker that has a screen. Users can interact with the screen to customize the ratio of ingredients or something and I had to design a class with public APIs to represent the coffee maker, which will be called by the screen.

Did they ask you to produce output since it’s on codility? Or just explain the thought process