Thinking about tech screenings for senior software engineering candidates: What’s the right level of difficulty for a screening during an interview?

If its developer role, its a medium/hard level coding situation which is given at the start of the session and we watch as they code. Honestly, I am not looking for a perfect run but I am looking for their thought process, how they go about collecting missing information and how they handle the pressure of the situation.

Are the SSEs required to code? If Yes, then depending on the job-level Leetcode Medium to hard questions would be suitable. All hard LC are used for Staff or above levels.