i installed Kubuntu day before yesterday everything was fine... found this problem yesterday morning then installed Debian KDE and then today Arch KDE .... but no solutionI've installed Kubuntu 20.04 yesterday and today it happened to me too. I hope we will find a solution.
i use Arch Linux bit anyway send me the repo let me check if they r available for arch or notIt started working! I've added 2 kubuntu repo and shutted down PC. Now I opened back and I can see new icons, themes etc. Can you see it too? If you can't I'll tell you what I did.
$ sudo add-apt-repository ppa:kubuntu-ppa/ppa $ sudo apt update && sudo apt full-upgrade -y
$ sudo add-apt-repository ppa:kubuntu-ppa/backports $ sudo apt update && sudo apt full-upgrade -y