Well the simple fact is that you can’t assess long term reliability on a new car. That requires many data points on many high mile cars to be able to see trends.
What you can do is look at brand reputation and what parts are carried over. If the car is new, but the drivetrain is a known quantity proven to be reliable in other models then you can generally assume that the drivetrain will maintain its reliability.
Didn’t Citroen do this 50 years ago?