Adding to this comment, the OP may want to be cautious about Firefox specifically. The Mozilla team has been pushing more and more anti-privacy "features" for some years now (perhaps due to Google's influence). Its forks, however and thankfully, try to fix those issues.
And regarding Mull specifically, and this may be an issue with my specific environment but I think it's worth noting, from my tests, downloading it from Aurora Store makes it crash on launch, while downloading from F-Droid store's default repository works just fine, so also beware where you get your browser from.