Check out the stickies in taming & bonding.
Budgies are naturally more likely to bond to other budgies instead of us. They all have their own personalities and some birds have more potential to bond with us than other birds do.
Don’t force yourself upon them, let them move to you (or not) as they wish.
If Blitz is openly aggressive to people, then consider why - It might be that she’s just going through a stroppy teenage phase:
or it could be that she has she not been shown enough patience in taming in the past by your friend, or it could just be her personality (she may just be quite cage territorial and actually behave nicely outside the cage).
At first, I would just leave her be. Let her see that you’re only messing about in her cage to clean and bring fresh food and water, and not to ‘bother’ her. When the aggression hopefully subsides, then you can work more on taming. If she’s very anti-hands, then clicker training may be a better way to go.