^ LibreWolf has been my preferred desktop browser for a g good while. It's a hardened version of FireFox. The new Mullvad browser seems to be the same idea, though I haven't tried it.
https://librewolf.net/
On #Android I have been using Bromite for a long time (hardened Chrome), but it seems the dev abandoned the project. Fortunately, another person is building new versions.
https://github.com/uazo/bromite-buildtools
For a hardened mobile Firefox, try Mull.
https://f-droid.org/en/packages/us.spotco.fennec_dos/