That's not too different than what I did. I left Google fall 2018, at the time thinking I'd write a video game. That morphed into doing research on 2D rendering, because building the infrastructure for that was more interesting and exciting than the actual game. For a while (not the whole time) it was pure unstructured time, no outside responsibilities. I rejoined Google a year ago with a research software engineer title, mostly because it was a better place to pursue this research than just continuing on my own.

Partly I'm posting this to support 'lapsedacademic's assertion, you can do good research in industry. It takes a certain element of luck to land a spot, but it also helps to be very passionate about the research itself.

I'm now writing a paper on an exciting GPU algorithm, but it's pure love, funding doesn't depend on it, it just makes a nice point on my list of accomplishments during perf time.