#hell the angel crowning Supreme Leader in CF's mural is basically this

[randomnameless]

Minor tidbit here -

Divine Right of Kings isn't the same thing as the Mandate of Heaven, the most important difference is that the Mandate can be removed - when the Divine Right of Kings is basically a permanent feature of bloodline X.

God-King Billy being overthrown by Chilon and Ananximandros would lose the Mandate of Heaven - but would still be the Divine rightful King.

Okay fine another hot 3H take

Divine right of kings and Mandate of Heaven is correct in-universe but only if the king actually has literal divine powers, aka Byleth.

Not Dimitri and AM even if he has archbishop!Byleth's blessing, he's still not the one with actual powers of Sothis. Not Edelgard, who doesn't want it anyway. Not Claude, who doesn't want it nor rules over Fódlan on that basis anyway. And probably not any potential successors Byleth would have either.

In the 3H world the divine right of kings is for one person and one person only, and that's Byleth whose claim to being chosen by divinity/actually being divine is literally correct. But it's factually and morally wrong if anybody else claims it. This is my unironic take as a toxic Byleth stan.