YET, Jesus chose to be born under Roman rule. That was planned very well, as the Romans adopted Christianity and the successor to Peter still sits not too far from Rome in the Vatican. It's called the Vatican because it was built on Vatical Hill, a MUCH older name to that hill. Rome had many hills.
The Vatican, as the "seat" of the pope, was begun one street level below the current level. If one descends downstairs there is one glass covered metal box and it says, quite simply: HERE LIES PETER.
The Romans were possibly developed by God JUST so that Christianity WOULD be spread so far...since Rome ruled MUCH of the known world at that time.
God did NOT have His only begotten Son born in Oriental Asia, India, Africa or the new world (North, Central and South Americas).
Gibbon got into trouble because he attributed a lot blame for the fall of the Roman Empire to Christianity.
He frequently unfavorably contrasts the otherworldly focus of the later Roman citizens, with the energetic practical outlook of their ancestors, and with the warlike nature of the barbarians.
He also has a lot in there on the various doctrinal disputes and heresies, and subtly makes fun of them and the disputants.
You got it right IMO that God’s plan did work out as Christianity provided the foundation for the tremendous moral and scientific progress which the western world has had.