https://privacytests.org rate Brave as the best browser.
FIngerprinting is not super easy. E.g. you might have a ‘unique’ fingerprint with FF but if it changes every time, than I would consider it actually a privacy feature. Did you have the same addons installed on BRave and FF while testing (as Addons play a part in Fingerprinting)? And finally: A lot of fingerprinting techniques can be blocked before they even start (no JS, …). I feel like your opinion is rather one-sided.
As to why FF> Brave: Basically the Chromium argument. Diverse engines are better for the health of the web.