I'm not sure that that's realistic. A browser in 2025 is arguably more complicated than an operating system, and requires fairly large and expensive teams of engineers to maintain and grow.

Google has billions and billions of dollars to throw at Chromium; I doubt Brave has anywhere near that kind of money. The longer it stays fully forked from core Chromium, the harder it's going to be to pull in updates, and the more expensive it will be to maintain.