Similar, but not same whited-out everything
I will begin by assuring everyone that I really did try the troubleshooting steps as well as any of the other "fixes" that were suggested and even assured 100% "fix" in a couple of cases. I am weird like that: none of them fixed it even a little bit if there is such a thing in this case.
I am running Kubuntu 23.04 and am fully up to date as of August 12th, 2023...with the exception being the latest Vivaldi for Linux (DEB):
And the entire window, even though all of the tabs are open (as evidenced by moving the mouse cursor around the white, 100% opaque window) looks as if a noob on GIMP or Inkscape accidentally clicked the little paint can and everything suddenly looked ultra blazing white filled-in shape interior/center. The only way to close it is to feel around for the X button that closes most windows.
I cannot stress this enough (mostly because I have lost a lot of sleep stubbornly trying to fix it) but absolutely nothing worked. I even tried several ways that were not listed here. The only fix is not a fix: use Timeshift and go back in time to an earlier snapshot before enabling this update. It worked, only because I completely reversed any and every part of that update. Not something I would recommend if you are not prepared to lose a few things. Suggestion: save to a different drive!
And yet, as negative as this all sounds, please don't mistake it as canceling anything anyone might suggest. Please: I sound as if I have tried everything because I tried every suggestion that was already listed here and that I could think of (most of which was desperate trial and error stuff) and I may no longer be a noob, but I am barely out of "Beginner" Level or Stage and not quite Intermediate (IMHO). So what I am trying to say is that I am very much open to any other suggestions, like, for example, being able to upgrade because a sudo apt update is all right, but I cannot (other than GUI method as Discover) upgrade for fear of installing the updated version (see above) of Vivaldi. But I prefer CLI update & upgrade which AFAIK includes everything that can be upgraded. For now, just update and Discover, by which I can pick and choose my upgrades. Obviously. Still, Please: help? Thank you!
@MichaelTheGamer Hi Michael, so just to be clear have you tried what is suggested here? https://forum.vivaldi.net/topic/88243/vivaldi-screen-corrupt-after-update/8 Sounds to me like you are experiencing the same Ubuntu issue .
The method I used to track down my issue (the gpucache one) was time shift back and then install each system update one at a time and check if Vivaldi was still working.
That's how I determined it was the libllvm13 update and found the solution using "libllvm13" and "Vivaldi" as my search terms.
You will have to do something similar to figure out what update is effecting Vivaldi on your machine and then you will have a better chance of finding the exact solution.