Below is a render of my object:
I'm using freestyle, but it has these small failures:
The freestyle settings are the defaults.
I tried to tweak the thickness, position, angle, lighting of the scene. Nothing worked.
Before posting the question, I looked at some of the same topic right here on this forum, but none of them seem to be the same problem:
Freestyle : problem with visibility
Edit 01:
The object has overlapping planes, this is the side view:



