I keep intending to reinvent my own controller with an RP2040, but life gets in the way, so for the second year in a row, I’m using a Pixelblaze to control the 950 LEDs on my Christmas tree. It’s a continuous string (well, 19 strands of 50 lights connected), put on the tree in a zigzag pattern and manually mapped to a vaguely triangular 2-D shape. The patterns are mostly as downloaded from the Pixelblaze repository.

I’d highly recommend Pixelblaze for getting a fairly complex setup working quickly.

https://youtu.be/hu-RQx_NpAY