As a fork, it is essentially a new version of an already Jepsen-tested system. That meets your definition of "a lot better" than "untested bespoke algos".
I am just evaluating your logic in the form of a reply, so you can see it at work. The same issue you describe happens often across multiple versions of a system.
The part of Redis that were Jepsen stressed, Redis-raft more recently, and Redis sentinel, for which the numerous flaws were pretty much summed at "as designed". No part of KeyDB has gone through a Jepsen style audit, all of which are untested bespoke algos.
