Now, the largest icon on the toolbar is 32x32 pixels, but this looks terrible on a 5k monitor. My monitor resolution is about 5120x2880, which is consistent with iMac 27 inch 5K, but the edges of the toolbar icons look very blurry. I used a 225% zoom. I don’t know if this is related to it, but I think the toolbar icon size should be at least 48x48px.
As a comparison
The Rhino For Mac icon is so clear and sharp