I worked for a startup as a data scientist, where I built and managed one of our data measurement/reporting systems. The company would routinely overstate how well their product worked, but I largely chalked it up to "fake it until you make it" -- but, they also never really worked on the "making it" part. So, our metrics quarter-after-quarter were spun and contorted to make it seem like we were still doing well. It got to the point where there were three of us that knew the real numbers, and our c-level was the only one allowed to share numbers both internally and externally. I stopped going to all company meetings because I started getting physically ill seeing/hearing the lies being told to the company, and having people comment or ask me questions after.
A new employee came in to my team, saw what was happening, and reported it internally. They did an "investigation" (but, somehow didn't interview me or anyone else who would have backed up what they had reported). The investigation found no wrongdoing and the reporting employee was told to leave.
Then, suddenly, the company decided to IPO. And those horribly misleading numbers made it into our S1, the investor decks, and continue to be routinely repeated on quarterly earnings calls. I left the company because of these issues, and now vacillate between reporting it to the SEC but figure they'd likely do nothing except burn my bridge with one of my longest employer tenures.
Anyway, you made the right decision to leave. Companies like that will never prioritize the right things, even when they're in more stable places. There are always trade offs to be made in early stage companies, but there are some things that you still should be doing regardless... there are other companies out there that take this stuff more seriously and act more ethically, but this kind of behavior is shockingly prevalent in the startup world.