Some brushes don't work very well. Here's an example.
You have a Sharp Pencil (Tilt) 2 px.
It doesn't show at all until increased to at least 5.
I thought maybe it was something to do with the "Tilt" in the name.
But other tools have similar problems.
And back to the Sharp Pencil, once it does agree to draw, it turns out to be highly jittered and separated dots. Can't draw a connected line.
I first tried it with a 1000 x 1500 sheet.
Then the same thing happened with only a 600 x 900 sheet.