As an interviewer, what you do seems to make sense and I do similar interviews. Removing the pressure of memorizing leetcode question algorithms (yes almost everyone has to memorize for leetcode hard to solve <1hr, most will need to memorize for medium) puts both sides in a better mood.

I also observed starting a process with easier questions still filters out the bad candidates (80%+). Once a candidate 3-4 rounds more open ended questions seem to be much more discriminative anyway.