I think Universal is paying similarly to WDW (or at least that's what I'm finding according to Indeed). However, according to my sister's former Disney coworker that left WDW for Universal, he said the biggest change was the workplace culture. Universal has a WAY better workplace environment than Disney does. If I were to guess, it probably has to do with Universal employees not having to abide by a super clean, family friendly image that Disney employees do.
However if you read Indeed and Glassdoor reviews, a consistent theme that comes up is hands off management, long hours, low pay and terrible treatment from guests so this is not a Disney exclusive problem.