This is the important one!

Using the 8-way output requires installing the Adafruit_NeoPXL8 library in addition to Adafruit_NeoPixel. You can find these through the Arduino Library Manager (Sketch→Include Library→Manage Libraries…)

Adafruit_NeoPXL8 library use is explained in its own guide:

Adafruit NeoPXL8 FeatherWing and Library

Obviously the FeatherWing and ESP32 pages are not relevant to this particular hardware, but please do read the Overview, RP2040, SCORPIO and NeoPXL8HDR pages.