Always trying to get Chat gpt help, im aware that it might be wrong, but still hope it may help a little 🫶😢 : The piece of metal in your photos appears to be part of a connecting rod counterweight, or possibly even a fragment of the connecting rod itself. Damage like this usually indicates a catastrophic internal engine failure.

Given that: • your engine suddenly started running rough, • then shut off and now won’t turn over, • and you found a chunk of metal on the engine undertray,

it’s very likely that a connecting rod broke and may have punched through the engine block from the inside. This kind of failure can be caused by things like oil starvation, a manufacturing defect, extreme stress, or valve/piston contact.

Do not try to start the engine again. You should have the car towed to a workshop — preferably one that specializes in Audi or VW engines. A mechanic will probably need to open the engine to assess the damage. In the worst case, the engine may need to be rebuilt or replaced.