I also install cuda stuff from nvidia driver repository (using ubuntu 20.04 and needed cuda 11)
/etc/systemd/system/systemd-suspend.service.requires contained symbolic links which point to /lib/systemd/system/nvidia-resume.service
removing these symbolic links made suspend work again.
another symptom was: systemctl suspend was not working but pm-suspend was working.
You saved my day.
I also install cuda stuff from nvidia driver repository (using ubuntu 20.04 and needed cuda 11) system/ systemd- suspend. service. requires contained symbolic links which point to /lib/systemd/ system/ nvidia- resume. service
/etc/systemd/
removing these symbolic links made suspend work again.
another symptom was: systemctl suspend was not working but pm-suspend was working.