I don't really mind these factors, for me, it is more about which university would provide a better course for civil engineering and which university will give me a better chance at finding a job after graduating. Would Monash be better as it has prestige and the ATAR requirement is higher?
If employment is your main goal, then I wouldn’t necessarily be looking at prestige and ATAR requirement to guide you. ATAR requirements are from demand by high school graduate hopefuls applying for that course, so doesn’t really show employability from said course, whilst prestige doesn’t always mean it’s “better” for employability, just has a better reputation because Monash ranks higher in uni rankings in general. (note: these rankings often use research as one of their main contributing factors, so if you’re not interested in engineering research, Monash may not be the best choice for you personally.)
I would be looking at availability or incorporation of placements, work experience, internships and practical applications, and certain uni rankings that factor in employability and teaching quality specifically e.g. QILT survey to help determine employability from the course.
On top of this, you might want to consider commute times to uni and uni atmosphere into your decision too.