I've a couple like this, either you swivel the brush through 90 degrees, oh, ad I also add an extra angle adapter to give me further reach (the lightweight plastic ones) I have found this more effective than a gooseneck.
If it is still too deep to reach then I take off ladder, lean ladder against balcony railings and do it from there.
I don't climb over the railings mind, I just pole them off the ladder.
Ian