RGBW Pixel Drivers Released for ESP32, Raspberry Pi, Arduino and ESP8266.
Given that these are serially chained. You either need to know what you have plugged in and explicitly tell it so, or do some trick play:
Plug the output of the end of the chain back in and then send a test pattern. From that you can calculate how many chips you have there.
And people will worship your awesomeness when you plug random things in and “it just works™”
Sadly, work makes me sick of computers so I seldom have time to do anything other than think about it ^^;