I've always thought there is a third type - Optimizer - but you call it Systematizer. So in my terms systematizer is one akin to collector. Probably, not that good for being engineer, but still good at building ontologies, categorizations, and such. In other words, those who you call Systematizers are really two. The real-time guys - good sense of time [they can accurately predict wall clock time without looking at the clock], good prediction, focused on optimizations, can be good lawyers, bookkeepers, mathematicians. And Collectors, who are slow, but steady, accurate, and... can be sadists at times. I am sceptical of MBTI, and this one https://www.psy8.net/ has more explanative power and easier to use by laypersons. In the vector psychology system (it's a trait model, not type model), Optimizer has orange as his color, Implementor is probably Red+Green (from what you described - the one who starts and who is eager to help), and your described Systematizer, as I claim, is a mixture of orange and brown - so my point being to separate those two. Red is a leader type - they are in the future. Orange as I said realtime. And browns are in the past, they love history and collecting items. Reds like to start things (sometime others are needed to complete what they started), browns can finish them. There are also blacks - those are good team players, love their mothers, but they need to be told what to do to be effective. There are also violets - those have deep intuition, etc, and Red leaders without violet need to listen to them.

In terms of vector psychology you described Red+Green and Orange+Brown+Violet. My point, however, is that dominant Brown can be it's own type of engineer (not sure how succsessful though). Also, men usually have only 1-2 dominant vectors, and women usually have almost all.

PS. Forgot to add, that Oranges are seeking profit most of the time. Stereotypical Western countries society is build by them... for themselves.

(I am not affiliated with the psychologistd behind psy8, just a fan)