You're still imagining a centralized solution with a single source of truth and less power than Git. Git history is a directed acyclic graph, not a single linear timeline.
There is at least one database that exists which does support a Git-like DAG for transaction-time temporality: https://terminusdb.com/
It should also be pointed out that "temporal databases" usually offer a lot more besides a linear transaction-time history. Although I've not seen anything that offers a DAG for valid-time histories yet :)
