I had a great experience interviewing with the developers—they were collaborative and provided helpful hints when I got stuck. I had a machine coding round in which I was asked a grid-based problem (which I won't spoil here). I solved it with some struggle, as it was my first time giving a machine coding round, then dove into performance optimizations and my thought process behind the approach. I received positive feedback afterward. This is exactly how frontend interviews should be: build something real, then geek out on the details and how to improve!
I regret not preparing enough, as based on the interviewers, it seems like a good company.