A few things you can try:
sudo prime-select nvidia
On Demand may cause crashes.
You might try the grub parameter intel_iommu=off if you are using Intel integrated with Nvidia dedicated.
You might refresh the Nvidia drivers (I agree about 535 drivers being itchy):
Thoroughly remove Nvidia drivers
sudo apt remove --purge '^nvidia-.*'
Install Nvidia drivers
sudo ubuntu-drivers install
Add X-Swat team repo
sudo add-apt-repository ppa:ubuntu-x-swat/updates
Upgrade Nvidia Drivers with X-Swat updates.
sudo apt update && sudo apt full-upgrade