Who issued the decree that the Jewish captivity could return and rebuild Jerusalem?

It was Cyrus

Isaiah 45:1
Thus saith the LORD to his anointed, to Cyrus, whose right hand I have holden, to subdue nations before him; and I will loose the loins of kings, to open before him the two leaved gates; and the gates shall not be shut;

And so we know, that Gabriel carried a prophetic truth to Daniel (chapter 9) AND that God uses heathen kings as a “marker”….the things they say, the choices they make….
Did not Augustus decree a tax upon the world?
And thus Jesus arrived in Bethlehem (See Micah 5:2)

When rulers speak?
What evil or good they plot comes from outside themselves

Proverbs 21:1
The king's heart is in the hand of the LORD, as the rivers of water: he turneth it whithersoever he will.