LibreWolf
FreeFirefox with every phone-home path removed
An independent Firefox fork that ships with all telemetry, crash reporting, sponsored tiles and Pocket recommendations removed, uBlock Origin preinstalled and strict tracking protection on by default. No account, clean from the first launch, no about:config marathon needed.
Why we picked it
Firefox is already privacy-friendly, but it still ships with telemetry on, sponsored content on the new tab page and Pocket bundled in. LibreWolf's job is unglamorous: strip all of that out, then set every privacy-related switch the way a hardened setup would.
Out of the box you get uBlock Origin already installed, fingerprinting resistance enabled, and cookies wiped every time you close the browser. For most people that replaces an afternoon of following an about:config hardening guide.
Two costs to know upfront. First, DRM is disabled by default, so Netflix and Spotify Web simply will not play until you turn it back on in settings. Second, there is no silent background updater like Firefox's — you update through winget, Homebrew, Flatpak or by downloading the new build yourself. If you are the type to ignore updates for six months, weigh that seriously.
One more thing: strict fingerprinting resistance makes a handful of sites behave oddly — for instance, a page's dark mode may not follow your system setting. That is the protection working, not a bug. If you can live with these, it is the most privacy-complete browser you can get without configuring anything yourself.