I've owned VW/Audi/Porsches for decades and on all of them the heated seats worked quickly and were really hot, especially on full blast. The seats in my 19 R take a long time to get warm and never really get hot, even on full blast.
Is this normal for them or something I need to have the dealer look into?
I'll let you know what the dealer says, but I fully expect them to tell me that they're working fine. I may play with the temperature thresholds with OBD11 if they say they're fine