[SpicyLemonZest]

It's not that difficult for people smart enough to get a FAANG job. Personally, I've heard anecdotes from people who can't understand leetcode problems even when given the solution. Professionally, I've seen multiple people who were clearly trying to recite a memorized solution for an interview problem, but just weren't clever enough to do it properly or talk about how it works.

[opportune]

For all the complaints about whiteboarding, it does filter out a lot of people who can't seem to generalize problems or are weak at either problem solving or coding. I don't see how anyone who has given technical interviews could say whiteboarding is a waste of time, unless they are not good enough at whiteboarding to be able to productively give such an interview.