We should not be talking about ethics if we're talking about Mozilla either. From shameless extension backdoors to not blocking trackers from Google on purpose, it's all over the place when it comes to ethics and privacy. At least Brave directly challenges Big Tech by making bolder decisions to block them instead of being afraid like Firefox, enabling trackers and not providing any privacy against Google.
What Brave has done with respect to privacy features, Firefox couldn't even do it in decades:
https://brave.com/privacy-updates/
I do understand that Brave is a chromium fork and that they depend on Chromium for patches but this is still a FOSS browser that is independently funded and has better statistical chances of survival than Firefox. Brave's MAU is very good, almost doubling every year since its first release. On top of that, they're the only existing company that challenges Big Tech search engine monopoly by actually providing a great privacy focused search engine that is also independently indexed.
Firefox is a series of unfulfilled promises and failures. An untapped potential ruined by management.