How to add new charecters to a Lottie Animation

I downloaded an animation from LottieFiles, and I want to change the text of the animation.

What I have tried

I tried using the Lottie online editor, but it didn't work, the text was not updating correctly, so I tried to manually edit the JSON file

What I found

I noticed that the JSON file has an array named chars this array does not contain all characters, bingo!

Looks like the Lottie online editor does not add the chars to this array, so I need to add the characters of my string for the animation to work. (this is my hypothesis)

The char has the following structure

"chars": [
  {
    "ch": "W",
    "size": 150,
    "style": "SemiBold",
    "w": 99.9,
    "data": {
      "shapes": [...]
    },
    "family": "Gilroy"
  }
]

Question

How can I add new characters?

I don't have experience with Adobe After Effects, is there any way to find the data for each char or an easy way to extract this info from After Effects?