I also undecided to buy jetta or not. (Currently driving polo sedan)
Those belt or bearing i opt out during service for my polo, i only change when it got some scratches line on it....

For dsg issue, i found this video anyway https://www.youtube.com/watch?v=vOEIptAJpyo

I asked a fren work in SC about the new mecha failing rate, he said still got a few come in for mecha replacement once in a while, but definitely much more better compare to last time.

To be safe get tiguan better as it is 6 speeder (wet clutch)