Hello Kieran L,
Welcome to Microsoft Community.
Let me kindly explain to you that panel self-refresh is a function of Intel graphics control centers, not Windows systems:
How to Enable and Disable Panel Self Refresh (intel.com)
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But there is a key message in this link:
Note Panel self refresh is available only for embedded DisplayPort 1.3 (eDP 1.3).
That's probably why you don't see this option in the Intel Graphics Control center on the Surface Pro 7.
But let's revisit your Surface symptoms. From your description of the problem, your Surface Pro 7 keeps freezing. If you want to troubleshoot this problem, I would first recommend checking your event viewer or reliability history to see if there are any critical records when the device freezes, as these are the key to identifying the problem.
It would be unwise to offer a recovery plan without this critical information.
Best Regards,
Mitchell | Microsoft Community Support Specialist