Help with level shifting and ledstrip
Such a level-shifter is designed for a (relatively slow) I2C bus, it's unlikely to keep up with the very fast signal required for a WS2811 LED strip.

My first try would be to use the strip directly, with 5V power and the 3v3 data output of the ESP. Could very well work.

Next try would be a 74HC buffer for the 3v3 -> 5V conversion, for instance two gates from a 74HCT00 (one would invert the signal).