Most likely: You will become their product that’s it. Be sold as part of their audience and then crypto-bros can invest into you and search advertisers will get you watching their ads so you will eventually invest into a token + have your local browsing history analyzed + your searches spied by their search engine (but it won’t be Google they promise, and they will keep their promise).

At the origin, Brave was supposed to be an adware that replaces the ads of the website with theirs.

Just pick your poison but all browser developers need money to live.

The only way to be sure a browser works in your best interest would be if you accept to pay, and nobody wants to do that.

See what has happened with Neeva.