The VPN they installed was disabled and they could not activate it without user interaction. And the only reason they did this is so when you click "activate VPN" in the browser, it works immediately.
On top of that, other businesses employ(ed) similar tricks. For years and years and years, Dropbox on macOS did a very specific hack to give itself more permissions to ease syncing. Hell, Firefox injected ads for Mr. Robot via a surreptitiously installed invisible extension.
Still a boneheaded move by Brave, just like adding their own affiliate link to crypto links (if none were added) to generate extra revenue for the company at no extra cost to the user. But that is even further in the past.
At any rate, they also fund or develop a bunch of anti-ad tech and research and make it open source / publish it. The defaults of Brave protect your privacy much better than Firefox's defaults. And so far, their BAT concept is the only one that is a legitimate alternative to an ad-funded internet.
Brave is everything Mozilla wishes it had become.
And yeah, my bone to pick is warning others not to fall for Brave’s slick PR. Companies that act that way can pay the price.
I’ll never trust them again after that.