Arkana rough running

Sounds like an exhaust leak maybe? I had similar issues with my old car after hitting a curb. Check for hissing noises or dark stains around the exhaust pipes. Could also be ignition coil, oxygen sensor, or even a clogged air filter, but exhaust leak seems most likely with those symptoms.

Where exactly should I be looking for the leak? And how would a crankshaft sensor or timing belt issue present?

Check the exhaust manifold and along the exhaust pipe seams, especially near joints and the catalytic converter. As for crankshaft sensor or timing belt, those usually cause starting problems or very erratic idling, not really jerking under acceleration. But exhaust leak can definitely cause that jerking. I'd get it checked at a workshop anyway.

Thanks. Took it to the workshop. Turns out it was a leak in the exhaust system, just like you thought. Cost me 265€ to fix.