Master Camshaft Sensor Fault

Sounds like a classic camshaft sensor issue, especially with those symptoms. The stalling and poor starting point towards that. Have you tried reading the error code? That would confirm if it's indeed the camshaft sensor. Also, does it seem to misfire at all, especially when cold?

Yeah, I read the code – it's pointing to a camshaft sensor fault, but I'm wondering if it's actually the sensor or something else, like a timing issue. And yes, it does misfire a bit when it's cold. Could the encoder wheel on the camshaft be damaged?

The encoder wheel is indeed the more likely culprit given the symptoms, especially the misfire and stalling. It could be damaged or misaligned, causing the sensor to send incorrect signals to the engine control unit. Get it checked ASAP, because prolonged misfires can damage the catalytic converter. Replacing it yourself can be tricky without the right tools and knowledge of the engine's timing. A workshop visit is highly recommended.

Thanks for the advice! Took it to the workshop as you suggested. Turns out, the encoder wheel on the camshaft was indeed defective. They replaced the camshaft sensor and encoder wheel and recalibrated everything. Cost me 695€, but it's running like a champ now. Appreciate the help!