There is a difference, and it’s between SU 2016 and 2020 on the identical hardware and Style settings.
This is on an iMac 27" Retina 5K late 2015 model. Radeon R9 M395 2GB graphics card with standard Apple drivers.
Left hand side, SU2020, opening the file given by the OP above.
Right hand side - SU2016 - same file saved back to v2016.
Styles show Edges, no profiles.
I noticed this earlier - can’t remember which upgrade - possibly between 2016 and 2017, or a year or two later.
I seem to remember it was in response to increasing resolution screens. SU looked too fine to be readable on original Retina and Hi-Res Windows screens. As well as too-fine lines, the inference point highlights were too small to distinguish between types. For the Mac only, there was a fix posted by a user which substituted larger icons for the inference points.
You got there as I was writing this post. That’s what happened.