Nice. Relatedly, as someone who has a few years of experience, how does one become a principal engineer? Anything I should know or do to get to that level?
I think most important aspect is experience, the second most important would be leadership. There is little point being a principal engineer if the intuition and experience you can bring to bear aren't embraced by your team so the soft skills definitely count. The role generally encompasses tasks that go beyond writing code, architecture being the most crucial (and technical) but you will also be expected to take part in hiring, making strategical and tactical decisions, etc.
Generally you get there through a senior or staff engineering role where you can demonstrate the technical and leadership aspects. I would focus on mentoring your more junior engineers and taking part in force multiplying efforts, i.e tooling, processes etc.
