I saw those on Pinterest, too, so you probably saw this one. It's sold along with the old standard rails you posted up above. It's a little updated version of the old standard ones.
I had another idea, but I couldn't find the right pictures on your thread to see if there's enough room by your steps. My steps are between my raised spa and sun shelf. Until this summer, I held onto the edges of those when using my steps - more for balance than anything. So I wonder - If you had a thin stepped wall built on the deck next to the steps. I can't draw on a computer (or phone), but the wall would mimic the steps, so as you went up or down, you would have the correct height to hold onto. It wouldn't have to be very high. You might not need many 'steps' to the wall. The best thing would be for you to determine the number and heights of the wall steps as you are actually going up or down the steps. You could use boxes for a mock step wall.