To combat a Chrome hegemony you need strong opposition, not a long-tail of weak opposition. Or in other words: Firefox needs to become more competitive. I (unfortunately) don't think having another 0.1% market cap browser is the solution, at least not for now.
Just to clarify: I'm in favor of Cloudflare donating to Ladybird, and I'm in favor of them building it! I just don't think that's the solution to combating Chrome dominance.