Freestyle: very unclean lines in 2.80 / Cycles


my client asked if I could create a technical drawing from the already rended pictures in othographic view. So I thought Freestyle could be a simple solution. Unfortunately my settings bring up horrendous results. Does anybody know how to create clean lines of the edges?

I have a lot for bevel, subdivision and boolean modifiers in my meshes. Does it have negative effects on this process?

Render at 200% and then super sample it to 100%.