I feel like I read a short story at one point where time travelers had spent a lot of time and energy making sure Hitler DID come to power because while he might have been terrible, every alternative was unfathomably worse. They had to keep stopping naive new time travelers from trying to kill Hitler because it could lead to the end of civilization.
This is what I thought of: https://www.abyssapexzine.com/wikihistory/
Am I wrong to think given unstoppable military technology, the Persians would definitely be the first Roman target?
You’d be absolutely correct. We in the modern day see Germania as the more pressing threat to Roman interests, since we know that from the 3rd century onwards motherfuckers are gonna be POURING across the border for several hundred years, but the Romans would have regarded the Persians, as a united empire and fabulously wealthy (unlike the horrifically impoverished Germanic tribes), as a much more enticing target for their efforts.
Yeah, as far as I can tell, they regarded the Germanic tribes as a bunch of munchkins, and used the Rhine and their various walls just as a way of defining the kid’s table. Eventually, of course, the adults fucked off and the children were left running the daycare.