happy to discuss their comparison in any other ways also
edit: just wanted to add I am not really considering Librewolf because I don’t like the idea of using something as complex as a browser when it’s maintained by only a handful of people.
Simply hardening Brave or Firefox per PG suggestions here does a lot for your privacy. I think you’re overthinking this trying to determine what is worth using more.
I suggest choosing a browser you like and harden it and you’re good to go. Privacy is not always complicated.
You’ll be fine, no matter what. In theory, I think with enough tweaking, you can apparently get Firefox somewhat close to Mullvad levels of protection, but depending on what your threat model, how you want your web experience to be, it’s probably not necessary.
But I do want to say, Betterfox is not recommended. You’re going to need Arkenfox for this.