I thought this ("split brain"?) was
a solved problem in the dark days long before DevoPS.
I seem to recall one mostly forgotten set of vendors calling it something like "disaster tolerance"; other similar options may have existed elsewhere.
Then the commodity side of the industry decided it was too hard or too expensive or too unfashionable and started sprouting BS like "eventual consistency". I mean, EC probably works ok for presentation-layer stuff where there is no correct answer and the money comes in anyway, but for stuff where things are either right or wrong and there's real stuff at stake, it seems like it might be time to look again at stuff from a couple of decades ago, before the knowledge is lost forever.