@rinring Just be aware that apt upgrade (or whatever you use) will immediately cause issues again unless you mark the package - sudo apt-mark hold opera-stable.

At least the downgrade gives you stability to be able to export things you need before wiping your profile, though.

No, you're not alone - I had what looks like exactly the same issue, albeit on Xubuntu/Xfce.

I did raise a bug report, but it's dangling, alone and unloved. To summarise, I saw this arrive with 99.0.4788.31 (the same as you), but reverting to an earlier version fixed it immediately (I went for 98.0.4759.6 from here). Upgrade again, and the problem came back - downgrade, and it vanished.

What seemed to fix properly it was clearing out my profile (~/.config/opera). I'm assuming there's a change in a particular flag (e.g. HW acceleration settings, or how shaders are handled) that isn't carrying over properly between versions.

You'll have to handle restoring passwords, bookmarks, extensions and the like, obviously.