For troubleshooting, I recommend
For trouble shooting recommend https://community.kde.org/Plasma/Wayland/Nvidia, checking whether all kwin backends are installed (kwin-wayland-backend-* on Ubuntu). Sometimes there's also a problem with the missing OpenGL backends of Qt. An easy check to see whether there is a problem with the proprietary driver is to try out whether the problem also exists using nouveau.
All of Wayland is based on EGL. What you are referring to are EGLStreams vs GBM which are both libraries using EGL. Nvidia drivers now support GBM for all supported GPUs via a support library that comes with the driver (libnvidia-egl-gbm https://download.nvidia.com/XFree86/Linux-x86_64/510.39.01/README/gbm.html). There should be no difference in the GPU generation used.
@Zamundaaa@mnglw xorg Apps don't crash when the compositor crashes, you can just switch out compositors/window managers. But xorg Apps crash when the xserver is crashing
@klangcola I'm not commenting on whether ot should be a show stopper or not. Just that it will eventually come also for non-Qt apps with MRs from KDE contributors to other projects.
@meiko60 newest Nvidia drivers are at the moment 535.xx. you could maybe try upgrading to se whether the situation changes. It's easiest to get new Nvidia driver when following the instructions for installing CUDA. You typically don't need to install all of the CUDA SDK and could for instance just install the package cuda-drivers
@meiko60 why do you think that the reason for the freezes is the graphics driver. Isn't Linux completely freezing typically a running out of RAM (when you haven't set sufficient swap partitions or swap files). On KDE, you can enable the classical Ctrl+alt+del key to reset the xserver/Wayland (advanced keyboard options). Could you check whether this still works when the freeze occurs? Are there any special things in your system log?
@tubbadu as other said, you should not create a PR from your master branch. You can still change the source of your PR using gitlab web UI (at least I think you can change after the initial creation. You may also temporarily remove the branch protection from the master branch using gitlab web UI in the repo setting to move this specific PR forward
@Sina@MartinR xorg supported exchanging the compositor before (kwin --replace). I believe xorg didn't support clients surviving a crash of xorg itself.