Systemic and systematic are seemingly very simiar words, originating from the same root, but with very different meaning.
Both terms related to the term system.
Systemic is a scientific term meaning relatedto or originating from a system as a whole. It is a synonym of holistic, something where elements are interrelated, and each part influences and interacts with the entire system.
Systematic relates to something that is carried out in by using a regulated or organized procedure, and, when fully built up, will constitute a system.
Very often it relates to a series of steps, which, if performed, the same result will be brought about.
In summary, the difference is that systemic means something matters to the entire system, while systematic means something organized or arranged according to a clearly defined and organized set of plans.