leetcode is a bastard. I fucking hate it with a passion.
Its almost useless as a way to learn how to be a better coder, as most of the "fastest" answers are unreadable.
But if you are using it as a basis for interviews, you are more likely to bump into someone who has trained on that particular question.
I'm not sure what the answer is, as other said, pair programming is kinda the answer. Maybe debugging something in your code base.
I guess my experience with different, because I never had to grind leetcode. I had some basic algorithmic lesson at my University (and a short adventure with competitive coding) but that's all. I never had a technical interviews where that was a problem - either there was no typical coding question, or a simple sanity check exercise. Instead we discussed some problems and thinks related to the job. I understand my experience is not typical - partially maybe I'm currently in the field of it security - but that still doesn't justify participating in the broken process with tools like this. If a company hiring process is broken just... walk away? Let them burn with leetcode grinders with no real experience that they'll finally hire.
I think because google et al started doing coding tests like this, everyone else does.