Librewolf is not really a good idea.
As mentioned in this thread, they are sometimes behind on updates for Firefox, but also on the preferences themselves. They rely heavily on Thorin’s work on arkenfox, and the main guy behind that work is apparently away from the project, which means they are having a hard time implementing what they need regarding the privacy/security aspect of the browser.
Here’s a recent talk they had on the arkenfox repo for people interested (starting here with ending note):