Control Panel > Mouse > ThinkPad > Slow ---[]- Fast slider almost all the way to right

sudo sh -c "echo 240 > /sys/devices/platform/i8042/serio1/serio2/sensitivity"

This is separate to speed settings for mouse pointer

On my X1 Carbon 6th, this helped but not much. I put up with a stiff trackpoint for couple years (that's how I depend on one :)), until it hit me! Sticking a folded piece of paper (or similar) into the base of the eraser lifts it up and makes it feel smooth as butter! Problem solved! I would give myself a Nobel prize for discovering this if I could!

I'm also on an X1 Carbon 6th gen! I will try this out. Thanks much.