Mozilla doesn't block ads and trackers by default so I would say Brave takes protecting users privacy more seriously as they block all that by default. They also provide tor browsing as an option for even more privacy with the possibility to browse onion sites. Something Firefox has refused to do for some reasons.
When using Tor it is important to be indistinguishable from other Tor users. If you can be fingerprinted by user agent, screen size, fonts, add-ons, or numerous other indicators, then the anonymity set of your browsing behaviour essentially becomes just you.
That's why the Tor browser is setup to be as homogeneous as possible. Using Tor within Brave does not provide the privacy that users might expect, and Brave even point that out in their website. Hiding your IP is a good start alongside blocking known trackers, but it's only one component of properly avoiding tracking online.
Partially incorrect. The last Firefox release enables tracker blocking by default on new profiles. You can switch it on at any time in your existing profile if you’d rather not wait for Firefox to do so for existing profiles.
