It's going to take years once it actually renders pages correctly to not only be fast but also secure.

And then it's going to take at least a decade for it to build the necessary ecosystem and ancillary tooling (use. Devtools) that other major browsers have.

And very likely unless it gains significant funding it will never catch up.

At the end of the day, browsers are absolutely crazy expensive to develop. It takes a significant number of engineers not only to maintain it but to build new features and keep up with web standards.