I've noticed quite a few people are not so happy with the cursor controls, this reminds me of R6 Siege when it first came out, but after they lowered the deadzone alot the controls became quite fine. So the deadzone between zero movement and full speed could have the sweet spot right there. Otherwise the full speed needs to be quite fast to get around the screen, but just add some smoothness to the center stick.
Very happy to see Kerbals on Xbox!
Cheers