At a huge company at Google, there's resources on everything imaginable, including other trades like product management and sales (which I'm interested in). Does it make sense at this stage in my career to spend a lot of time looking into those and learning?
You can do it, but don't spend too much time on it.
Unless you don't like software engineering and want to pivot out of the field entirely, I highly recommend staying focused at this stage in your career and building that initial foundation. What that means for a junior engineer is that you should get extremely good at coding. This means that you should be able to build out any medium-sized project with high good velocity and good quality while requiring minimal hand-holding.
If I were to put a number on it, I would spend 5-10% exploring these outside areas. A common failure mode I see among earlier-in-career engineers is distracting themselves too much researching these other pillars, which includes many E3s I saw at Meta.
In terms of how/when to invest more exploring these other areas: