C was never made for PQ - only for MQB
so you must downgrate them to B + proper data set
Spacewalker is right, and probably this could be one issue.
Looking into ETKA for the Sharan and Seat Alhambra till 15.07.2019 5Q0907686B was used.
After that time VW switched to 2Q0907686B.
So there must be a reason why they did not jump to "C".
Even if you can Flash "C" and Code the "C" to PQ35, probably it will not work because of some incompatibility which was introduced with "C"
I will try my setup with "B" when i find time ...