I just investigate with CC, the second sudo command was needed. Now Opera starts.
The issue is clear. Opera rev 440 now requires the gpu-2404 content snap (for GPU/hardware acceleration support on Ubuntu 24.04), but the slot is not connected.
Fix:
sudo snap install mesa-2404
sudo snap connect opera:gpu-2404 mesa-2404
Then start Opera normally. This connects the GPU provider that Opera 129 requires.
Why this happened: Opera updated to use a new GPU content snap interface (gpu-2404) for better hardware acceleration on Ubuntu 24.04. The snap was updated but the required mesa-2404
provider snap wasn't automatically installed/connected.