Molly and Blakeney both have short hair, I wonder if Ruby would be tempted to copy? Then again it wouldn’t be very Victorian I suppose. I’m actually surprised Ruby doesn’t research and cosplay elaborate updo’s to match the aesthetic she is trying to portray.
A shorter hairstyle would suit Ruby's features, actually. Well, anything would be better than the limp single-length look. I don't think a pixie or short bob would work that well, but a medium-length cut would freshen up her look a lot. Or a medium bob cut to the shoulders with some soft layers. I don't know all the terms for these cuts, heh.
I had Ruby hair (not blonde though) my whole life - no fringe, no layers - until I decided to have it cut short into a textured pixie cut. I haven't gone back to my long hair, though I think about it occasionally. My hair is thick and dense, though, so it was hard to do anything complicated with it. Even a bun required braiding and a lot of bobby pins. Ruby has more styling options, since hers is medium or thin.
Hair is something that I found difficult to change, personally. I got a lot of pressure from my mother to cut my hair, but I am glad I waited until I wanted to do it. When I made the decision, I felt almost 100% certain I would be happy or at least able to live with the result, and that was important to me.
I think she just doesn't have the skills to do anything more complicated than a ponytail. Her attempts at putting her hair up in a simple bun were pretty bad for a 21-year-old and she can't even do a French braid.
I couldn't French braid my hair either

There was just so much, and it was heavy. At the end of the day, if I had put it in a ponytail or bun, my head would feel bruised underneath...
I get the feeling Ruby doesn't go to a salon, ever. That alone would help, even if she keeps it long.