Noisy chain while riding

Hi there, i'm an happy owner of a cube cross race pro 2021, since summer 2023. Ridden for like 2k km so far. After the last cleaning i noticed a noisy clicking chain (sadly i can't remember if it did so after purchase / before the clean – i think it was more quiet beforehand). I made a couple of Pictures and a Video.

I'm a new bike mechaning and want to learn to do things by myself. Things i tried so far:

1. indexing and adjusting limit screws / b screw (followed a yt-video)
2. tried a different chain (no improvement, i think even more noise)
3. checked alignment of chain through pully wheels
4. the hanger isn't bent (it's bent by design)
5. i don't think anything is bent. I think the cage of the pully wheels (however thats called) isn't bent any more than it meant to
6. rear and front derailleur running smoothly and quietly, if chain is detached

Is the cassette really worn out already? 2k km seem a little low for replacing.

Thank you in advance. If there are any more thinks you need (pictures), just ask.