Thirdly: yes, Arduino’s digitalWrite() functions are slow. The writers of those functions have made some choices and I think they probably made the right ones given their audience.

If you aren’t familiar, the digitalWrite() function is one of the key functions Arduino gives you to operate its boards– specify the pin and the value (high or low) to drive it. It’s very ...

digitalWrite() is a built-in Arduino function that simply turns the digital U/O pin specified on or off - in this case whatever is attached Arduino pin D13, or LED_BUILTIN.

Arduino microcontrollers have added Python to the range of compatible programming languages. Others can be used, and not just Arduino's own IDE app.