Maybe librewolf, but Waterfox is a drop-in replacement. Same extension “store”, gets updates quickly, install on every OS I’ve tried (which is usually windows unfortunately) is equally as smooth as Firefox, compatible profiles, etc, etc, etc. You literally just go to a different website to get the installer. It’s harder to install FF developer edition.

They both use Gecko under the hood and can install any Firefox Add-on. If you want something truly different, try a Goanna-based browser like Pale Moon or Basilisk

Tired: Firefox

Wired: Floorp, Midori, Mullvad Browser, SeaMonkey, Waterfox, Zen, GNU Icecat

Inspired: Basilisk, Pale Moon

Speaking of “I use arch btw”