So, does it shave arm hair well? After breadknifing, once you get it to shave arm hair well, then you are ready to advance.

I suspect part of your issue is coming from slurry management. You mentioned going slow, which is fine, but you also have to account for the fact that moisture will evaporate, requiring you to add more water because you don't want dry coticule slurry on your hone. So, then you have the potential of adding too much water, diluting out more slurry than you want.

Asking us if your razor isn't sharp enough because it's not passing HHT is an exercise in futility. We have no way of knowing. You really have to take a razor that you know works well, calibrate the test with your hair source, and make it meaningful to you. If I had your razor in my hands, with my hair source, then I could answer.