There really isn't much point in using Librewolf these days when projects like Arkenfox or Betterfox can provide a pretty robust user.js file which when used in conjunction with CanvasBlocker and Ublock Origin can more or less provide the same functionality.

An argument can be made for Mullvad Browser though as it provides much the same functionality as the Tor browser does albeit without access to the network. If your threat level mandates that you use entirely separate browsers for certain activities then that would be a suitable alternative to hardened Firefox.