[TUTORIAL] Installing official NVIDIA driver in Optimus laptop

[hassoun]

Every step went perfect till this point:

xrandr --verbose|grep PRIME

I always get:

PRIME Synchronization: 0

And also updating grub

update-grub
/usr/sbin/grub-mkconfig: 10: /etc/default/grub: nvidia-drm.modeset=1: not found

I use KDE desktop. So I assumed my display manager is SDDM

So I have this file with the following content

cat /usr/share/sddm/scripts/Xsetup
#!/bin/sh
# Xsetup - run as root before the login dialog appears

xrandr --setprovideroutputsource modesetting NVIDIA-0
xrandr --auto

What could be wrong?