Jujutsu is essentially an alternative front-end or “porcelain” to git, both magnificiently simplified and powerful.
I tried it after using Emacs Magit for about six or seven years, and jujutsu is really easier to use than git and useful if one wants a tidy public history of changes (with “tidy” and “public” as Linus Torvalds recommends). Plus it is fully compatible to git as backend - other contributors will not even note you are using it.
Currently it works just as frontend for git, but it theoretically supports other backends too. Allegedly Google has their own experimental internal cloud+db based backend for big monorepos.