1) I don't know what software stack you're using (I'm on Debian Linux) but acceleration is a supported setting on both the TrackPoint and the TrackPad. Personally I find acceleration vital to them being usable. On Windows there's QL mouse accel filter to customize the curve to an advanced level. On macOS there's an older software called ControllerMate that let you set a custom acceleration curve. I don't know if it works on modern systems though.
2) I don't know what 3-finger DND is because I use 1 finger to DND. Mind explaining a bit more? I've got 3 fingers bound to Mission Control which might be a default and I find quite handy.