After installing Nvidia drivers, I have strange graphical artifacts

I have Kubuntu 22.04 LTS (dual boot) with GeForce 9400M. I tried to install Nvidia driver 340.108 using PPA:

sudo add-apt-repository ppa:kelebek333/nvidia-legacysudo apt updatesudo apt install nvidia-340-updates nvidia-340-updates-dev xorg-modulepath-fix

After rebooting it seems to work, but I have graphical artifacts at the bottom of the screen:

What should I do with drivers to get rid of this?