You may happen to like how system-ui looks on your system (macOS? Windows?); but do you have any idea what it looks like for the person reading your resume, perhaps on Linux with a custom theme, or on an Android device where the vendor chose to ship some brand-specific UI font? Or on a 5-yr old version of the OS, or on the version that'll be current 5 years in the future?
IMO system-ui is hardly ever a wise choice for content.