I see what you mean, but in my experience there's this tendency where you think you're testing for "X", but you aren't really.

A whiteboard FizzBuzz might be actually testing for memorization, deliberate interview prep, extrovert tendencies, etc. And not for any kind of actual technical skill. Failing the FizzBuzz could also just mean high social anxiety.

True. I find I have to iterate on my processes quite a few times before I squash these issues.

They're conceptually similar to software bugs - inevitable, often surprising and impossible to fix all at once.

Beyond Fizbuzz, the standard algo type interviews are just optimizing for time spent on Leetcode or length of time since finishing College.