According to the newest (2025-08-12) privacytests.org test it is pretty good but for desktop Mullvad Browser and Tor Browser are best.
As for Android: Tor Browser and Firefox Focus were best at that time though neither block advertisements. Firefox Focus does not support installing add-ons and it is highly recommended not to install one in Tor Browser as it will make you stand out from the rest of its users.
Personally I can recommend Ironfox to you. It is the continuation of DivestOS’ Mull Browser (not Mullvad). It is hardened Firefox and asks you on first launch if you would like to install uBlock Origin. I presume most people tab on ‚yes‘, so not installing it would actually make you stand out
According to the newest (2025-08-12) privacytests.org test it is pretty good but for desktop Mullvad Browser and Tor Browser are best.
As for Android: Tor Browser and Firefox Focus were best at that time though neither block advertisements. Firefox Focus does not support installing add-ons and it is highly recommended not to install one in Tor Browser as it will make you stand out from the rest of its users.
Personally I can recommend Ironfox to you. It is the continuation of DivestOS’ Mull Browser (not Mullvad). It is hardened Firefox and asks you on first launch if you would like to install uBlock Origin. I presume most people tab on ‚yes‘, so not installing it would actually make you stand out