Plasma session goes blackout after leaving it AFK (workaround exists)

Desktop Environments Plasma
16

So I tried the

systemctl enable nvidia-suspend.service
systemctl enable nvidia-hibernate.service
systemctl enable nvidia-resume.service
systemctl enable nvidia-persistenced.service

and I think I got a result but

I am not sure if I inputted or understood
sudo nano /etc/kernel/cmdline and appended to end: nvidia.NVreg_PreserveVideoMemoryAllocations=1 nvidia.NVreg_TemporaryFilePath=/var/tmp

Is that done on the terminal? I typed nvidia.NVreg_PreserveVideoMemoryAllocations=1 but got command not found.

Thanks for your patience. This is pretty new to me.