I’ve been watching this thread. I believe I’m running into this issue as well (Ender 3 S1 Pro). I haven’t run the X-Twist Compensation yet (I need time and a feeler gauge) but I did create an install of OctoPi+Stock Marlin to see how that performs and the difference in bed mesh is, well, pretty stark:
Marlin:
Klipper:
I ran a 50x50 mesh because I’m a glutton for punishment but my smaller meshes all have the same problem.