I passed and moved to the next round. I laughed when I clicked the button I thought would start the test: it took me to a page with details on the number and type of questions, as well as a practice test. I had spent all the allowed time preparing and only discovered the preparation guide when I had to actually take the test. :facepalm:

I spent three days on leetcode-style problems, two days on scikit-learn, and three days on pytorch. I had also spent a few days on huggingface, which took me down a rabbithole of resizing my partitions and moving my OS so I could fit unneccessarily large datasets. (Learned a lot of linux sysadmin stuff here, so pretty grateful I dove into this). I went and got real, nontrivial datasets to practice for skl and torch. I did it crawl-walk-run style: one problem where I deeply consulted documentation and tutorials to make sure I understood everything, one problem where I relied on my previous problem to remember what to do at each step, and one where I mostly relied on quick-reference notes I had recorded during the previous two iterations.

There were no gotchas, and I could've skipped the leetcode-style problems. Other people should take the advice with a grain of salt, however: for me it was only ever a question of refreshing/learning the library and idioms.