The smaller window is much more performant, so it would seem to be the pixel allocation which causes this --- except, I'm getting a delay when dragging to rotate w/ a stylus which I don't see when using a trackpad.

Arguably, Moment of Inspiration 3D and Shapr3D have fully eaten up the "3D modeling program designed for use w/ a stylus (or Apple Pencil)" market, but there are _dozens_ of us! If possible, please test w/ a stylus and keep that usage in mind --- it's a good fit for the creative sorts who would use it.

If you want some "Blue Water Sailing", it might be that doing a version for Android would offer a market free of competition, and there are innovative devices there such as the Wacom Movink Pad 14 (which can also be used as a display tablet on Windows/Mac devices I believe).