I doubt the difference in the maintenance cost is more than say 5%. Most of the maintenance doesn't involve transmission.
Not sure. My father's Honda Pilot has a 9-speed German transmission. Service every 60k. Dealership wanted $900.
Is that on the manufacturer schedule, because that's insane?
Yup: https://www.shopdap.com/blog/post/service-schedule-for-mk7-a...
Every DSG VW needs it at 40k interval.
The DSG version of my VW requires transmission fluid flushes every 40k! These dual clutch systems are incredibly complex.
My g/f's Acura has a 9-speed Automatic transmission. Can't imagine what it's like to work on one of those.