You could recton the entire shadowlands in a simple steps.
Zovaal, the Jailer we engage is but a construct - Android, made by the first ones to replace his previous iteration, which is a copy of the real king of the damned.
As many theorist speculated, there has being a war over the cosmic forces, and The Order is the one who one the last war. taking over Death’s realm gates, not the realm it self.
Now Oribos is but a funnel, a conduit per se which transfers all souls to their machine of afterlives. Effectively leaving everyone imprisoned in the eternal cycle and feeding First ones appetite.
The real death king, could look similar to the leaked concept art and or to the giant head in Pit of saron, or maybe that head is one of his minions.
Now the First ones create 2 Zovaals, the one we fight is the second, having memories conflict with the purpose, he believing is the true arbiter and by default the death god / king.
As for the Real Death realm’s Lord, king or God. He isn’t and all consuming being, he isn’t a judge, he is the lord of the eternal resting place, which has nothing to do with any living mortal believe.
His power can be borrowed and or used by other, a kin to the elementals, but in a much lesser way, main example is the scourge. He doesn’t look for a fight unless it breaks the balance.
Lastly you can re link this to all the original Wc3 plots and some wow plots effectively retconing what was brought forward in Shadowlands.