Your last point is laughable.
Yes Brave cannot make commits to Chromium, but it makes changes to their own repos (well, obviously) and can also accept/reject changes Google makes to Chromium.
In my opinion, Firefox is more of a slave to Google than Brave will ever be because they rely entirely on Google giving them money for the default search engine.
Is Brave's revenue model scammy? Maybe. But at least they aren't Google little bitch.