Good luck, architect.
If you have been searching for the you are likely looking for the holy grail of concise, structured, and high-signal information. While Rylan Liu (a noted engineering leader and author of System Design Interview: An Insider’s Guide ) hasn't officially released a standalone "fundamentals PDF" under that exact name, the search term reveals a hunger for a condensed, cheat-sheet style document that captures his core methodology. System Design Interview Fundamentals Rylan Liu Pdf
Your interviewer isn't looking for the perfect system; they are looking for the reasoned system. When you pick a component, state the trade-off aloud. Good luck, architect