i cant really help you. this is main kernel parameters: nvidia-drm.modeset=1 nvme_load=YES rw panic=10 root=UUID=***************************** nvidia_drm.fbdev=1 systemd.machine_id=********************.
and i dont use NVreg_PreserveVideoMemoryAllocations=1 or nvidia-xxx.services and my sleep works perfectly fine. with hibernation i always had trouble and as i dont really need it, i havent tried to fix it.
as i mentioned i am on nvidia-open-dkms. i added panic=10 and removed nowatchdog when i tried to prevent hard restarts when i got kernel panics, but now they are gone with nvidia-open-dkms.