I’d love a round brush added to the available pens with the ability to set opacity and color. This would make it easier to create circular dots we could use as circular bullet points in productivity tracking journals. It just looks cute and feels satisfying. GoodNotes does this with the highlighter brush. I wouldn’t mind having it as an additional brush with opacity settings.
Also a fan of the GoodNotes round brush
An example in GoodNotes. The highlighter brush, makes perfectly round dots as seen in the bullet points in this pic. If you make a line across with the highlighter, it automatically straightens the line (see the long pink line with rounded edges)