Insignia Engine Stalling

Those symptoms suggest an EVAP issue. The tank ventilation valve, or purge valve, releases fuel vapors to be burned. Clogged hoses are common. Does it stall immediately on starting, or only after warming up?

Stalling mainly occurs after reaching operating temperature, after at least 20 minutes of driving. Could a faulty purge valve itself cause this, and how do I differentiate it from clogged hoses?

A faulty purge valve could cause that. If stuck open, it creates a constant vacuum leak, leaning the mixture and stalling the warm engine. It's tricky to differentiate without equipment. I'd suggest a professional diagnosis; they can use smoke tests and tools to pinpoint the cause.

Took your advice and had it inspected. It was the tank ventilation system, specifically clogged hoses. Repair, including hose replacement, cost 175€. Car runs smoothly now. Thanks!