Every privacy blog provides a doom and gloom scenario for every browser. The section on Firefox is all over the place, since it refers to versions from even 7-8 years. Guess that site is more of a problem list rather than providing a fair assessment of anything.
For amusement, you can also read a comparison on Mozilla's site which is surprisingly not that stilted.
Read our comparison of Firefox and Brave browsers on features, privacy, and ease-of-use.
www.mozilla.org
You can continue using what you "feel" is better but the point remains that Brave provides a "less data leak" facade on the outside because they are trying to capture all the data internally through all their integrations and monetize that data. The fact that they promote open source and keep clamping down on all forks that try to remove their integrations speaks volumes of their intentions.
No, Mozilla is not Devil Incarnate because then you don't have any idea what the big tech companies are up to. I believe Mozilla is just incompetent compared to Brave, which is smart at fooling people in the name of privacy. As a foundation, Mozilla is still doing a lot for the web as a whole and honestly I feel it needs to provide a real alternative to Chromium.