libreWolf seems to be built regularly using the latest version of Firefox. If it ends up using the nightly build of of firefox nightly or dev edition in the future it could release security updates even faster then firefox "mainstream" itself. LibreWolf does not appear to be maintained by a single person like you implied. Its a relatively new project it can either go one of two ways: become popular and gain lots of supports + maintainers, die a slow death. After having actually used it for a few days it seems good to me. I'll continue to evaluate it as my daily browser.