Your question is Most Difficult Tech Problem. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
What's the most difficult tech problem you've ever solved?
Choose one specific problem and explain why it was difficult, what your responsibility was, how you investigated it, and what you ultimately changed. Focus on your decisions, trade-offs, collaboration, and the measurable outcome rather than listing technologies. A strong answer should follow a clear STAR structure and include what you learned or would do differently.