Based on my deep research reading Wikipedia, Angel Dust seems to be someone who's either neutral or a hero. Moreover, as a Morloc she isn't really affiliated/engaged with either the X-Men or Francis or anyone like that.
Is there any information from the film’s creators on why she ended up as a villain, serving Francis?
Related: " Why is Negasonic Teenage Warhead so different in the Deadpool film? " and " How was Angel Dust able to successfully fight Colossus? "