Ok, here, chew on this... I hadn't looked at this confusion for a while, but it, now, fits with the discussion... remember my saying with Insider Builds the blur was no longer AND I'd not made any changes? Well...
I just checked:
20H2, yes, I do have that set to Enabled & hence no blur. So long ago I'd forgotten about it.
BUT❗
The Insider Build, which IS NOT blurred nor has it been for quite some time, is set to Not configured❗ In other words, it should be blurry, but it is not.
Decided not needed to put snips to show (or prove) what I'm telling you.
Cheers,