…and this is with Steinberg Power scheme enabled, the computer is a desktop and did not sleep during this time.
When you say freezes, is the CPU at 100%?
No. Cpu is normal. Only Cubase is frozen, nothing can be done. After waiting for some more time, pressing keys and mouse clicks made the cursor into hourglass then it crashed.
Even with the Steinberg Power Scheme enabled, go into the windows additional power settings section and make sure nothing (like usb ports) are being disabled after a certain time.
This might be the culprit if your are using a Cubase version that uses a USB dongle.
Regards 
Thank you. If the e-licenser went to sleep while Cubase was running, that’s sure to cause a crash.