Many case studies read to me like school homework: they knew what the answer and the process were “supposed to be” according to the textbook, so made up the story to fit. In reality, as you point out, it’s never smooth and linear. It’s messy and loopish. If you’re doing a good job, you rarely end up with anything remotely like you anticipated when you started out.

abandon your dogmatic and idealistic view of the design process, and keep learning about how flexible, messy, and beautiful it is.

I don’t speak about the “ideal” design process for a simple reason: it doesn’t exist. Design is never linear, and all projects are unique. The point is to show and explain your path from the kick-off to the final result in the portfolio.

If you tell a story, include the details and the things that didn’t work and how you adapted to overcome the problem, the design manager will empathise with you. For the five minutes it takes to read your case study, they’ll be in your shoes. It’ll remind them of all the times when they had similar problems and it’ll make them appreciate you and your struggles as a designer.