Is this what you want to achieve?
The chord of the arc is so short that even a default 12-sided arc has too many sides. Reduce it to 4 sides before drawing it and it’ll work.
What are you modeling and how will it be used? Perhaps it would help if you scale the model up by a factor of 100 or 1000. Or use the “Dave Method”.
You would also find it easier to draw the entire shape if you draw it on a large rectangle so you can keep everything on the same plane.