I know those, but I do have osnap active most of the time and many other geometries are on the screen.
DragMode on ControlPolygon will make you also snap to everything else, so you have to continuously turn on and off the osnap.
Also, if you have gumball ON, the central white dot will prevent from using ControlPolygon dragmode if the control point was already selected, as said here Rhino8 WIP - Gumball
So it’s a mess of turning on and off gumball and osnap. Not a solution, in my opinion.
Currently i’m using Scale command, that lets me keep everything on while i “move” a point by scaling it nearer/away from one neighbour point. Not a good solution either.
The simple behaviour of the gumball (draggable without messing with osnap) would be best.