Actually, the current K'Hara are a totally different cycle of evolved Nomads, they're nothing like the Vanilla ones. It's like saying that the current Liberty house is just like Ancient Rome.
The lore plan is for different groups of humanity to come to talks with the Nomads and for humans and Nomads to generally leave each other alone like they do now. Select groups like the Order and Core will still fight them though.
Having a 'main' enemy in Discovery doesn't work, there can't be good vs evil, and even the Nomads vs Order vs Core isn't a war of good vs evil, everyone is morally grey, everyone is pretty much evil.
Currently, factions are and must be, political view point vs political view point, or money vs money, greed vs greed.
Discovery factions cannot be 'good' or 'bad', every Disco faction is morally ambiguous. This is why the Phantoms didn't work.
