Safe to keep the device drivers marked as not verified?

No worries. It is safe.

https://learn.microsoft.com/en-us/windows-hardware/test/hlk/testref/eb9bad1e-70b3-4f8d-a090-4ff15ee7b559

It depends on. From the screenshot, you can trust it as it is from Microsoft corporation.

It indicates that the driver hasn't been officially signed or verified by Microsoft. Unsigned drivers might be from unofficial sources or may not have undergone rigorous testing.