Acer Nitro VG270UG - No Sound

Hi, I treadted myself with a complete new gaming setup and bought 2 Acer Nitro VG270UG monitors. Set everything up yesterday and it all worked perfectly fine.

Today one of the monitors doesn't play any sound which it 100% did yesterday.

Things I already checked for troubleshooting:

Monitor is correctly set as audio device in windows audio settings (if I switch to the other one, it works)
DP cable is connected properly, already pulled it out and plugged back in both on PC and Monitor
Audio drivers are up-to-date
Monitor is on full volume and not muted in its settings
multiple PC restarts didn't help