Is NVRAM not working problematic?

I've been reading up a little on NVRAM, including the 'sudo nvram TestVar=HelloWorld' test to verify it's working. Turns out it isn't. Or at least, the value stored in the test doesn't persist between boots.

Question is, is this test reliable, what are the implications of it not working, and how can/should it be resolved?

I'm using EmuVariableUefi-64.efi and OsxAptioFix2Drv-free2000.efi, and the 'store nvram.plist on system partition' is not ticked in Clover configurator.

• iMessage works fine, facetime opens (never used it though)
• sleep and wake works 95% of the time (very occasionally after a prolonged sleep, macOS comes back up and shows the previously open apps, but when they are opened, they appear to restart as if the state hasn't been saved). Only since 14.4.5 however.
• Shutdown works as expected
• SIP fully enabled

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The system is:

Gigabyte z390 Auros Ultra
i9 9900k
SMBIOS Macmini8,1 (i9 imac didn't exist when I built this)
Mojave 10.14.5
Radeon RX 590 8 GB

Thanks.