Kevin, [Feb 17, 2021 at 7:58:10 PM]:

I unlocked the secret of driving a brushless ESC with arduino!

I pulled out the PAPR blower, and I always had trouble getting it to work consistently.

Arduino Brushless Motor Control Tutorial | ESC | BLDC – HowToMechatronics

In this tutorial we will learn how to control a brushless motor using Arduino and ESC. For this example, I have an outrunner BLDC motor with…

This tutorial unlocked it for me:

Arduino Brushless Motor Control Tutorial | ESC | BLDC

This was the key:

  ESC.attach(9,1000,2000); // (pin, min pulse width, max pulse width in microseconds)

The commands I was setting sometimes but not often reached the minimum width to arm the ESC.