I guess I'm catching up on the forum after not checking it for a while, so not sure if this is still useful...
Did you try the solution on wood?
I can't remember how much color change I saw in the vinegar solution, but I do believe it did change. And maybe it took a while. You can try the solution on a test piece to see if any ebonizing happens.
Things to try - make a bigger batch, stir/agitate the soaking wool more, give it more time to soak. I think I gave it more than a couple days with a small batch. This method depends on getting the vinegar in contact with the surface area of the steel, so these might increase how much reaction you are getting.
Also, I think I referenced the article in Fine Woodworking June 2019 last time I did this.