They are more privacy focused, but they are not "better" in an unqualified way. Mullvad and Tor especially are not recommendable for daily usage without significant asterisks, they have some features disabled and if you modify their settings at all, add extensions, or even log in to websites, you ruin their anonymity features.

Librewolf is nice, but it's basically just Firefox with Arkenfox pre-applied, and it lacks automatic updates which are important for security. If you have a package manager that's better, but by definition you'll still get updates slower than using Firefox and applying Arkenfox yourself. For instance Firefox 129 released on August 6, Librewolf 129 on August 10.