Tor browser for mostly anonymous browsing, Mullvad browser as default non-Tor browser (it’s basically an open source Firefox fork made by Mullvad and the Tor team), but I also still have a regular Firefox configured with Arkenfox’ user.js and some important extensions, as well as a Chromium with zero protections except uBlock Origin. I switch between those browsers depending on use case. Each browser has a different theme to make them distinct, the “insecure” browsers which I only use for rare exceptions (websites misbehaving in any other browser) have a red-like color. All browsers are being run sandboxed.