Using a Pi4 v 1.4 using WS2812b led resulted in PWM FAIL with error:
Code
[hyperiond LEDDEVICE] (ERROR) Device disabled, device 'ws281x' signals error: 'Failed to open. Error message: Hardware revision is not supported'
Solution was to use SPI as per the docs located at: https://github.com/jgarff/rpi_ws281x
Hope this helps someone that runs into the same issue.