Sounds like you are real close! I would not start making big changes just yet.
Often "going animal" right at the end with carefully increasing pressure and speed despite your fatigue can achieve the temperature you need to get a glowing ember. And once you get a sense of the speed and pressure needed you can go to both earlier in the process, making for a shorter though maybe more intense effort.
Try also varying the thickness of your hearth board and the size and position of your notch. Listen carefully to the sounds. Be sure to keep your spindle as vertical and steady as you can.
As others have said, different wood can make a difference, as can difference in moisture content, etcetera. But don't chase a lot of materials until you are pretty sure your technique is solid.
And this may sound silly, but consider taking a moment before you begin to think about and maybe give thanks for the sun, trees, soil, and all that you are using. I sometimes even ask for help from whoever might give it in releasing fire from the fiction and wood.