Firefox actually has a lot of telemetry that's opt-out rather than opt-in, and doesn't have many privacy protections. Librewolf comes with ublock origin (which blocks trackers and annoyances as well as ads), has extreme fingerprinting protection, and has no google stuff out of the box.
Great! Keep digging, keep asking the right questions and ultimately you will just collect enough reasons to simply not use any other browser, until something even better will appear.
Firefox is the Firefox we all really need and LibreWolf is the Firefox we deserve.
Firefox has telemetry and has become adware. Mozilla VPN ads pop up every once in a while. Sponsored bullshit on the home screen. Pocket integration with recommended/sponsored content. Mozilla's becoming what it set out to destroy unfortunately.
LibreWolf is Firefox without this garbage, plus more privacy focused defaults. Some of those defaults are rather extreme though so I recommend toning it back (such as deleting history/cookies after every session, and resist fingerprinting can screw up anything that displays time by not taking your time zone into account).