Coding LED Strip Pattern in WS2812


I am wanting to create an RGB LED mirror, similar to the image I have attached. I am currently trying to prototype this with a WS2812b and arduino uno.

What I am wanting to do is have 3 colors (green, white, red) smoothing pulsing. Eg if Green is peak brightness, then red is low and white is medium. Suppose to look like a a flag in the wind. Or another option would be to have the LED strip slowly pulsing thought all colors.

Right now I have been trying to do this with the RGB function and PWM, however I am having quite a hard time. I would say its both. I know how to drive it with the the basic FastLED using CRGB function but I cant get the color pattern.

Red, green, white is the main 3 colors I am wanting to display simultaneously.

If you guys have any advice or have any code that I could use that would be extremely helpful.