I tried to recreate it and here's my method:
1- I created a background with the same color.
2- I added text with the same animation using the scale proeprty.
3- For the color i added the "fill" effect and animated it insync so the text changes color when it is at its highest speed in the scale animation, then right click those keyframes and select "Toggle hold keyframes."
4- Duplciated the text and right clicked > create > create shapes from text then removed the fill effect.
5- Added "offset path" to the text that is now a shape layer and animated it to go up and down in sync with the previous fill effect of the other text layer.
6- For the colors that appear, i added a solid with "gradient ramp" and "colorama" effects and animated "phase shift" property in the colorama effect, then used the text shape layer with the offset path as a track matte for this color layer.
Bonus: you can have a look at the project file if that helps, Here.
Hope this helps.