No. There are not enough hours in the day, unfortunately. I did respond to the pixel size issue on GitHub. I think it's technically a KStars/Ekos issue, not a driver issue, but the driver could probably be enhanced to supply the values for the K70 so as to avoid the issue in the future.
I had done some initial profiling a while back to see how much time FITs conversion was taking on the Pi4. I was surprised to find it taking less than a second, which is a big improvement over the Pi3 and probably attributable to having more memory available. Unfortunately, this means that clipping and/or downsampling before FITs conversion is unlikely to help much--the bottleneck right now appears to be the transfer from the camera to the Pi4. I'm going to look into it one more time just to double check, though.