Cheap 1 mm pens produce scratchy lines:
More expensive 0.5 mm Pilot Precise V5RT pens produce well-filled lines:
Both of those are on plain paper. Better paper would surely improve the results, while moving the cheap pen further into sow’s ear territory.
For reference, the cheap pens use a collet holder:
The Pilot V5RT pens use a custom holder:
A 3D printer really simplifies making things!