I started having this issue after turning off hardware acceleration, and turning it back on fixed it for me (after a restart of windows explorer).
You might want to check in Opera settings whether or not "graphics acceleration" is enabled or disabled. If it's not on, try turning it on, then, you will need to either restart your PC, or restart Windows Explorer through task manager.
Hopefully this fixes your issue, if it doesn't, I'm afraid I'll be of no more help.
Images below show Hardware acceleration in Opera GX settings, and turning off Windows Explorer in task manager:
Opera Settings:
424b2725-8d4f-4ac4-b8f3-ef60829fd5c8-image.png
Windows Explorer in task manager:
5865b23f-5394-42c0-a95d-ce058941a73f-image.png