Wow... No recommendations? Not at all?
AdaFruit have a library for ws2812b matrices. But it uses their own NeoPixel library, not FastLED library.
Because you don't need a library to control them other than the normal WS2812 drivers. So it is hard to recommend one.What do you want a library to do for you that is not trivial to code yourself?
An advanced LED strip library when using the ESP32 is the Adafruit_NeoPixel.h. The ESP32 Adafruit_NeoPixel.h the library is written in C and uses some of the ESP32's OS, freeRTOS, library to facilitate operations.
if somebody already have done such thing and ready to share, why to reinvent bicycle?
Because if you can't reinvent the bicycle then you will never learn how to invent anything.
BS, I CAN reinvent bicycles and i did it so many times to be fed up with this.
Quite honestly I don't believe you.