Here's another thought that maybe only applies to intermediates like me - I wouldn't call any of her skiing in that video "slow".
When you're in bumps or any kind of terrain where you can't be mindless, things are happening very quickly - bumps are coming at you, you have to pick a line, you have to think about where to pole plant, you have to REMEMBER to pole plant, you have to think about where your weight is, etc.
All that can make it feel like things are going too fast, and everything is coming at you quickly, at which point you either brake, get out of control, or fall.
In other words it feels like you're skiing fast, mentally, even if it's not very fast physically.
So making those things as routine and automatic as possible will likely give you more control.
I know I'm not nearly there yet, but I'm working on it. And hopefully things will "slow down" (mentally) for me.
A few thoughts on learning to ski steeps:
Speed is relative. So is steepness. Everybody has their own comfort and skill levels. Continue to push beyond your comfort level, then back off and everything is easier.
It's too late If you have to think or remember much, even at a slow speed. Everything happens too fast to focus on more than a few basic things. Those things should probably be consistent turn-to-turn. Eventually, everything else comes from instinct.
The few things I think about: Keep my hands up. Keep my skis on the snow. Shoulders square with the hill. Use my skis as much as possible to turn, turn, turn. At one point that was turn, plant, turn, plant, turn, plant. . . Until my pole plants became instinctive.
Line selection is what I dedicate most of my limited brainpower to while skiing, especially in steeps. Where am I going? Where's the best snow? Most fun terrain? What are the odds that line is going to kill or maim me?
I used to stop frequently to pick a line in steeps and bumps. A fun challenge as I've improved is to choose my lines on the fly. That's a big part of the fun of skiing for me now, as I hope you can see in some of the videos I posted above.
It takes a lot of mileage to build skiing instincts and muscle memory. The more of that milage similar terrain and snow conditions, the better. Mileage in even more difficult terrain and conditions, pushing your comfort level, really helps with the psychological aspect (fear, uncertainty, doubt). It's hard to get mileage in super steep terrain, so take the opportunity when you have it.
I think the best analogy is learning to drive a car, particularly a manual transmission. There is SO much to think about when learning to drive: rules of the road, steering, shifting, braking, mirrors, fatal accidents, wrecking mom and dad's car, etc. It's overwhelming. Eventually, after enough mileage in enough different conditions, driving becomes instinctual. Driving becomes so ingrained some even choose, unwisely, to surf the web while driving. Thankfully that hasn't happened for skiing, yet.
That's all from my self-taught side of the tracks. I know others have different experiences and ways of learning. I just thought I'd share mine.