If you try to answer with an LLM, you'll have to copy-paste the question (or write it), wait for an answer, read the answer, understand it, correct it (because most likely it won't be 100% correct), and answer to your interviewer, all while pretending you are not doing that.
You may as well Google the question and try to find an already-existing answer while pretending you are not doing that, right?
My feeling is that the interviewer will quickly realise what you are doing.
There is no such thing as an impartial yet meaningful measure that can be equally applied across all candidates. You should be discussing your business, your issues, and the candidate's ideas (with some small practical examples) for how they can move things forward in the area they're applying for.
Someone's leetcode rating isn't going to move your business needle.
Meanwhile, it is not a complete assessment. You can do all the other things you've stated and leetcode will still add value.
The point of leetcode et al is to measure how able you are to solve problems which you have not seen before. It is not a comprehensive evaluation but a useful part of one.