Just FYI, I'm currently making some extensive loopback measurements with the Focusrite Scarlett Gen 4 (to characterize it) for distortion testing and have made one Scarlett-to-V3 Mono measurement. So far the Focusrite drivers have not been an issue. ASIO drivers in Windows 10 Pro in a laptop
@48kHz. I've also run it in an old Dell desktop with no issues that I can recall other than when the output over-drove the input.
As an aside, I have had a curious issue with the (very old) M-Audio Delta 410, but that card is a 1998 design. Still remarkably good considering. That issue may be the driver that was never targeted for Windows 10, but with proper REW settings I ultimately got it to work. But to reiterate, I've never had a problem with the Focusrite drivers, they seem rock solid with REW.