I'm really confused about the terminology in this post. I've been using a QHY294C Pro since it was released. In 11mp mode, A pixel is defined as 4.63um*4.63um. In unlocked 47mp mode, A pixel is defined as 2.314um*2.315um by the manufacturer. I always use these as the Bin x 1 values in plate solver settings (depending on camera driver mode) everywhere just like a monochrome camera. I do understand that underneath the driver at the hardware level, in the 11mp mode, the pixels in "this camera only" (SONY IMX294 BSI CMOS (Color version)), are Binned x 2. But that's irrelevant at the image level after the driver output.
As I mentioned before, I've had the same issue with these small pixel settings with my Mewlon 300. However, the new QHY Beta drivers are allowing 4x4 color binning on some of the new color cameras. I've not checked this out on my 294C Pro. This will make a big difference in plate solving slow scopes. In general, I do not treat my color cameras any different than my monochrome camera and always use the manufacturers specified pixel size.