So I’ve basically done a full rebuild - and the same issue was happening.
This all gets narrowed down to Focusrite’s interface and some level of confusion caused by their USB driver (18i8 gen2). Mind you I’ve tested EVERY combo and order with my interface and peripherals on the mobo usb ports and hubs.
I’ve tested 2 motherboards and CPUs and both had the same issue on Windows. My secondary machine (Mac) was working fine with the interface. Yesterday while I was reinstalling all my software after a clean build Cubase was also blocklisting all my NI/Melda plugins.
Today my 2i2 gen3 came in to confirm it’s the 18i8 gen2 interface. Voila, no more audio crackles and after a rescan all my plugins aren’t blocklisted anymore.
Insane an interface can screw a system up this badly. This will be the last USB interface I’ll ever use - and Focusrite at that…
Again, thx for all the input from you two. Think I’ll be keeping my i9 10900k (OC 5ghz @ 1.28v) - during the tests it grew on me 
What a poop show…