Neopixels are still broken on the esp32 with version 2.00.
Since the sdk was updated to v3.0 (and also 3.1) it has not worked. There was no changes around the RMT libs used output the waveforms,so it's a bit of a mystery. @jumjum is going to connect a digital oscilloscope at some stage.
The outstanding issue is here:
We have bigger issues with wifi not connecting at present with the latest sdk so will be reverting back to 3.0.x
The ESP-idf is a moving target - we update to get new features, and then other things break. It's very frustrating!