I would first try to set kwin rendering backend 1to Xrender, this uses the CPU and not OpenGL/GP so you can see if the OpenGL drivers are the issue. For me on NVIDIA control panel app I have more options for OpenGl and those helped me.

This page has some variables that let's you set some things and bypass kwin autodetection https://community.kde.org/KWin/Environment_Variables

I know it sucks that it does not work out of the box, at least you don't have Nvidia.