I want to make a banner (think Supermans 'Daily Planet' or a ball bearing ring (that I photographed and traced)). So I made a cylinder. It turned out well enough, but I would very much like to have a nice round edge from the front to side. How is that most easily accomplished?

I failed searching for adequate solutions

I guess the main idea is to have some sort of gradual color change across the edge. You can do it using a radial gradient on the cylinder fill with more than 2 gradient stops (put the center of the gradient in the center of the round bit and shape it accordingly).

Or you can maybe use a path shaped like a wide letter U positioned over the edge and blurred. You could also use a wide stroke and a radial gradient instead of the blur.

Search the images for candles or similar objects where you can observe what it feels like to have a rounded edge.