I am able to consistently reproduce this by upgrading nvidia-dkms, nvidia-utils and lib32-nvidia-utils packages to 525.89.02-1 and rebooting my computer. I don’t need to open any desktop applications - the flickering starts right away.
I’ve confirmed that this happens both on Plasma 5.26.5 and a custom Plasma build (<5.27). The issue is present on the SDDM login screen as well. I’ve also tried kernels 5.15.94 and 6.1.12 - no difference here.
It seems that everyone here is using rolling distros. Perhaps this problem is caused by some conflict with some newer software? Would you like me to provide any additional information about my system?