If you go to about:profiles, I'm pretty sure there's a button to open the profile folder. Move all the files and folders from the Firefox profile folder to the Librewolf profile folder and you should have your settings and (I think) extensions in Librewolf now. Not sure about passwords but someone here in the replies said you can just import your Firefox passwords into Bitwarden. Since you want to switch to Bitwarden anyway, you should do that. Saving passwords in the browser isn't very secure anyway.