Thanks for the written feedback (which adds to what I had gleaned in person).

There were actually multiple times during the first couple weeks when I (or my partner and I) would spend 4+ hours trying to fix one particular line of code, and Jonah would give big-picture answers about e.g. how linear regression worked in theory, when what I'd asked for were specific suggestions on how to fix that line of code. This led me to giving up on asking Jonah for help after long enough.

I think that what happened here is me having misunderstood what you were asking for, rather than any disinclination on my part to help you with individual lines of code. I will take this feedback into account.

Intermediate and advanced SQL, practice of certain social skills (e.g. handshakes, being interested in your interviewer, and other interview-relevant social skills), and possibly nonlinear models.

This is helpful detail regarding what you were looking for. Which topics would you have preferred to have been been dropped in favor of these?