Does Darksiders 3 have a 'New Game Plus' mode?
Solution 1:
It does have NG+ aka Armageddon mode as of Patch 4 of April 11, 2019.
Solution 2:
There is no NG+.
Not all games do have an NG+ mode, though since the previous installments did have an NG+, it might be understandable that Darksiders 3 would too.
However, it has been revealed that the Abyssal armour is to be released in a future DLC pack, there is potential that the "NG+ mode" will be released in a later pack as well.
Source.