[Cannot smooth brush edges?]

I've got bilinear selected and all drivers on my system updated, I'm still getting jittery edges on my brushes. The only smooth edge I can manage is with the stabilizer turned on, which makes it a bit too difficult to sketch naturally.  

Red strokes were done with my mouse while using my primary monitor rather than the cintiq, as a comparison. 

[Cannot smooth brush edges?]

Hello!

I'm using a cintiq 24hd and recently started using affinity photo and affinity designer. I can't seem to get smooth strokes for any brush I've tried so far; default, custom, messing with my own settings. They all have rough edges on every stroke. I've tried searching around for tutorials that address brush settings and rough strokes, but I think maybe my search terms just aren't strong enough to find helpful resources?

Here's some comparisons between Autodesk Sketchbook and Affinity on the same cintiq. 

All screen shots are at 100% zoom.

Thank you for any guidance!