> The candidate has been preparing for weeks for an assessment that has nothing to do with their actual job, and is being assigned multiple take-home challenges that take 4-8 hours of their time, etc.

Take homes are usually pretty fun, I don't mind building yet another carwash react-express-postgres for someone. Leetcode is a whole different story. My ability to solve DP and graph questions deteriorates if I don't practice it constantly! Truly the biggest waste of time is being expected to be a solid leetcoder