Nvidia needs a special setup to make suspend / hibernate work, see e.g.: https://wiki.archlinux.org/title/NVIDIA/Tips_and_tricks#Preserve_video_memory_after_suspend https://download.nvidia.com/XFree86/Linux-x86_64/565.77/README/powermanagement.html Most distributions don't set this up for the user, resulting in a broken out-of-the-box experience when returning from sleep. You can find a lot of user complaints about this online. As a safety measure, Plasma could disable sleep completely, when it detects a Nvidia card as the main GPU and the needed services: - nvidia-suspend.service - nvidia-hibernate.service - nvidia-resume.service are not active and /proc/driver/nvidia/params is missing "PreserveVideoMemoryAllocations" and "TemporaryFilePath".
This sounds like it could be made part of https://invent.kde.org/plasma/plasma-workspace/-/issues/64