For WS2812B LED circuits, the typical approach is to use a large capacitor (around 1000 µF) for bulk decoupling. However, if you require a very tiny footprint, you can use a small 0.1 µF MLCC for high-frequency noise filtering. Keep in mind that while a 0.1 µF capacitor is very compact, it won’t provide the energy buffering that a larger capacitor offers during high surge demands.
Would you like to update your schematic with a tiny 0.1 µF MLCC capacitor connected across the supply pins of your WS2812B LEDs for high-frequency decoupling?