I can somewhat understand the overall criticism, because Librewolf - as far as my understanding goes - would be in trouble without the work being done on the code upstream.

Personally, I know that this does not exist (yet), and to some people that put privacy above everything else with a more libertarian slant, this might sound like the worst option imaginable, but my "dream" way to handle it within the current economic system would be:

Have an open source, FOSS base, web-engine and all, developed with public funds similar to public broadcasting in many countries (Bonus if carried by international organisations instead of just national. Think a UN institution like UNESCO or WHO, but focused on making the internet accessible neutrally and to all). On top of that code, projects that want to put privacy above all else could still feasibly built projects like LibreWolf (an even Brave), relying somewhat comfortably on secure fundamentals.

I know, sounds like a dream, which it is at this point. But every other solution within the current economic status quo I personally thin of, I see no chance of enshittification not always encroaching and creating crises, if not outright taking over.