I work with headless Jetson Xavier NX (systemctl set-default multi-user.target).
I launch my program using ‘xinit path/to/script’, everything works fine but in about 10min screensaver (blank) comes up.
I tried to add xset s off and xset s noblank just before calling Xsession (default) with no result.
Just as in original post, solution didn’t work.
Maybe it works for people who load Ubuntu with GUI (gnome), but not for me.
One possible reason is that I launch new xsession every time device is powered on by using xinit.
I also have tried to use .xsessionrc with no avail.